Merge tag 'sound-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound

Pull sound updates from Takashi Iwai:
 "This became a fairly large pull request.  In addition to the usual
  driver updates / fixes, there have been a high amount of cleanups in
  ASoC area, as well as control API helpers and kernel documentations
  fixes touching through the whole tree.

  In the driver side, the biggest changes are the support for new Intel
  SoC found on new x86 machines, and the updates of FireWire dice and
  oxfw drivers.

  Some remarkable items are below:

  ALSA core:
   - PCM mmap code cleanup, removal of arch-dependent codes
   - PCM xrun injection support
   - PCM hwptr tracepoint support
   - Refactoring of snd_pcm_action(), simplification of PCM locking
   - Robustified sequecner auto-load functionality
   - New control API helpers and lots of cleanups along with them
   - Lots of kerneldoc fixes and cleanups

  USB-audio:
   - The mixer resume code was largely rewritten, and the devices with
     quirks are resumed properly.
   - New hardware support: Focusrite Scarlett, Digidesign Mbox1,
     Denon/Marantz DACs, Zoom R16/24

  FireWire:
   - DICE driver updates with better duplex and sync support, including
     MIDI support
   - New OXFW driver for Oxford Semiconductor FW970/971 chipset,
     including the previous LaCie Speakers device.  Fullduplex and MIDI
     support included as well as DICE driver.

  HD-audio:
   - Refactoring the driver-caps quirk handling in snd-hda-intel
   - More consistent control names representing the topology better
   - Fixups: HP mute LED with ALC268 codec, Ideapad S210 built-in mic
     fix, ASUS Z99He laptop EAPD

  ASoC:
   - Conversion of AC'97 drivers to use regmap, bringing us closer to
     the removal of the ASoC level I/O code
   - Clean up a lot of old drivers that were open coding things that
     have subsequently been implemented in the core
   - Some DAPM performance improvements
   - Removal of the now seldom used CODEC mutex
   - Lots of updates for the newer Intel SoC support, including support
     for the DSP and some Cherrytrail and Braswell machine drivers
   - Support for Samsung boards using rt5631 as the CODEC
   - Removal of the obsolete AFEB9260 machine driver
   - Driver support for the TI TS3A227E headset driver used in some
     Chrombeooks

  Others:
   - ASIHPI driver update and cleanups
   - Lots of dev_*() printk conversions
   - Lots of trivial cleanups for the codes spotted by Coccinelle"

* tag 'sound-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (594 commits)
  ALSA: pcxhr: NULL dereference on probe failure
  ALSA: lola: NULL dereference on probe failure
  ALSA: hda - Add "eapd" model string for AD1986A codec
  ALSA: hda - Add EAPD fixup for ASUS Z99He laptop
  ALSA: oxfw: Add hwdep interface
  ALSA: oxfw: Add support for capture/playback MIDI messages
  ALSA: oxfw: add support for capturing PCM samples
  ALSA: oxfw: Add support AMDTP in-stream
  ALSA: oxfw: Add support for Behringer/Mackie devices
  ALSA: oxfw: Change the way to start stream
  ALSA: oxfw: Add proc interface for debugging purpose
  ALSA: oxfw: Change the way to make PCM rules/constraints
  ALSA: oxfw: Add support for AV/C stream format command to get/set supported stream formation
  ALSA: oxfw: Change the way to name card
  ALSA: dice: Add support for MIDI capture/playback
  ALSA: dice: Add support for capturing PCM samples
  ALSA: dice: Support for non SYT-Match sampling clock source mode
  ALSA: dice: Add support for duplex streams with synchronization
  ALSA: dice: Change the way to start stream
  ALSA: jack: Add dummy snd_jack_set_key() definition
  ...

20 files changed, 1917 insertions, 713 deletions

diff --git a/sound/usb/6fire/control.c b/sound/usb/6fire/control.c
index 184e3987ac24..54656eed6e2e 100644
--- a/sound/usb/6fire/control.c
+++ b/sound/usb/6fire/control.c
@@ -25,8 +25,8 @@
 #include "comm.h"
 #include "chip.h"
 
-static char *opt_coax_texts[2] = { "Optical", "Coax" };
-static char *line_phono_texts[2] = { "Line", "Phono" };
+static const char * const opt_coax_texts[2] = { "Optical", "Coax" };
+static const char * const line_phono_texts[2] = { "Line", "Phono" };
 
 /*
  * data that needs to be sent to device. sets up card internal stuff.
@@ -327,14 +327,7 @@ static int usb6fire_control_input_vol_get(struct snd_kcontrol *kcontrol,
 static int usb6fire_control_line_phono_info(struct snd_kcontrol *kcontrol,
 		struct snd_ctl_elem_info *uinfo)
 {
-	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
-	uinfo->count = 1;
-	uinfo->value.enumerated.items = 2;
-	if (uinfo->value.enumerated.item > 1)
-		uinfo->value.enumerated.item = 1;
-	strcpy(uinfo->value.enumerated.name,
-			line_phono_texts[uinfo->value.enumerated.item]);
-	return 0;
+	return snd_ctl_enum_info(uinfo, 1, 2, line_phono_texts);
 }
 
 static int usb6fire_control_line_phono_put(struct snd_kcontrol *kcontrol,
@@ -361,14 +354,7 @@ static int usb6fire_control_line_phono_get(struct snd_kcontrol *kcontrol,
 static int usb6fire_control_opt_coax_info(struct snd_kcontrol *kcontrol,
 		struct snd_ctl_elem_info *uinfo)
 {
-	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
-	uinfo->count = 1;
-	uinfo->value.enumerated.items = 2;
-	if (uinfo->value.enumerated.item > 1)
-		uinfo->value.enumerated.item = 1;
-	strcpy(uinfo->value.enumerated.name,
-			opt_coax_texts[uinfo->value.enumerated.item]);
-	return 0;
+	return snd_ctl_enum_info(uinfo, 1, 2, opt_coax_texts);
 }
 
 static int usb6fire_control_opt_coax_put(struct snd_kcontrol *kcontrol,
diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c
index 3b02e54b8f6d..62c25e74f0e5 100644
--- a/sound/usb/6fire/firmware.c
+++ b/sound/usb/6fire/firmware.c
@@ -316,7 +316,7 @@ static int usb6fire_fw_fpga_upload(
 
 	while (c != end) {
 		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
-			buffer[i] = byte_rev_table[(u8) *c];
+			buffer[i] = bitrev8((u8)*c);
 
 		ret = usb6fire_fw_fpga_write(device, buffer, i);
 		if (ret < 0) {
diff --git a/sound/usb/6fire/pcm.c b/sound/usb/6fire/pcm.c
index ba40489b2de4..36f4115eb1cd 100644
--- a/sound/usb/6fire/pcm.c
+++ b/sound/usb/6fire/pcm.c
@@ -679,25 +679,16 @@ int usb6fire_pcm_init(struct sfire_chip *chip)
 void usb6fire_pcm_abort(struct sfire_chip *chip)
 {
 	struct pcm_runtime *rt = chip->pcm;
-	unsigned long flags;
 	int i;
 
 	if (rt) {
 		rt->panic = true;
 
-		if (rt->playback.instance) {
-			snd_pcm_stream_lock_irqsave(rt->playback.instance, flags);
-			snd_pcm_stop(rt->playback.instance,
-					SNDRV_PCM_STATE_XRUN);
-			snd_pcm_stream_unlock_irqrestore(rt->playback.instance, flags);
-		}
+		if (rt->playback.instance)
+			snd_pcm_stop_xrun(rt->playback.instance);
 
-		if (rt->capture.instance) {
-			snd_pcm_stream_lock_irqsave(rt->capture.instance, flags);
-			snd_pcm_stop(rt->capture.instance,
-					SNDRV_PCM_STATE_XRUN);
-			snd_pcm_stream_unlock_irqrestore(rt->capture.instance, flags);
-		}
+		if (rt->capture.instance)
+			snd_pcm_stop_xrun(rt->capture.instance);
 
 		for (i = 0; i < PCM_N_URBS; i++) {
 			usb_poison_urb(&rt->in_urbs[i].instance);
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index 2b92f0dcbc4c..bcee4060fd18 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -9,6 +9,7 @@ snd-usb-audio-objs := 	card.o \
 			helper.o \
 			mixer.o \
 			mixer_quirks.o \
+			mixer_scarlett.o \
 			pcm.o \
 			proc.o \
 			quirks.o \
diff --git a/sound/usb/card.c b/sound/usb/card.c
index f61ebb17cc64..1fab9778807a 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -112,15 +112,13 @@ static struct usb_driver usb_audio_driver;
 
 /*
  * disconnect streams
- * called from snd_usb_audio_disconnect()
+ * called from usb_audio_disconnect()
  */
-static void snd_usb_stream_disconnect(struct list_head *head)
+static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
 {
 	int idx;
-	struct snd_usb_stream *as;
 	struct snd_usb_substream *subs;
 
-	as = list_entry(head, struct snd_usb_stream, list);
 	for (idx = 0; idx < 2; idx++) {
 		subs = &as->substream[idx];
 		if (!subs->num_formats)
@@ -307,10 +305,10 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
 
 static int snd_usb_audio_free(struct snd_usb_audio *chip)
 {
-	struct list_head *p, *n;
+	struct snd_usb_endpoint *ep, *n;
 
-	list_for_each_safe(p, n, &chip->ep_list)
-		snd_usb_endpoint_free(p);
+	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
+		snd_usb_endpoint_free(ep);
 
 	mutex_destroy(&chip->mutex);
 	kfree(chip);
@@ -323,16 +321,6 @@ static int snd_usb_audio_dev_free(struct snd_device *device)
 	return snd_usb_audio_free(chip);
 }
 
-static void remove_trailing_spaces(char *str)
-{
-	char *p;
-
-	if (!*str)
-		return;
-	for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
-		*p = 0;
-}
-
 /*
  * create a chip instance and set its names.
  */
@@ -416,7 +404,7 @@ static int snd_usb_audio_create(struct usb_interface *intf,
 				USB_ID_PRODUCT(chip->usb_id));
 		}
 	}
-	remove_trailing_spaces(card->shortname);
+	strim(card->shortname);
 
 	/* retrieve the vendor and device strings as longname */
 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
@@ -430,7 +418,7 @@ static int snd_usb_audio_create(struct usb_interface *intf,
 		/* we don't really care if there isn't any vendor string */
 	}
 	if (len > 0) {
-		remove_trailing_spaces(card->longname);
+		strim(card->longname);
 		if (*card->longname)
 			strlcat(card->longname, " ", sizeof(card->longname));
 	}
@@ -475,14 +463,14 @@ static int snd_usb_audio_create(struct usb_interface *intf,
  * only at the first time.  the successive calls of this function will
  * append the pcm interface to the corresponding card.
  */
-static struct snd_usb_audio *
-snd_usb_audio_probe(struct usb_device *dev,
-		    struct usb_interface *intf,
-		    const struct usb_device_id *usb_id)
+static int usb_audio_probe(struct usb_interface *intf,
+			   const struct usb_device_id *usb_id)
 {
-	const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
-	int i, err;
+	struct usb_device *dev = interface_to_usbdev(intf);
+	const struct snd_usb_audio_quirk *quirk =
+		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
 	struct snd_usb_audio *chip;
+	int i, err;
 	struct usb_host_interface *alts;
 	int ifnum;
 	u32 id;
@@ -492,10 +480,11 @@ snd_usb_audio_probe(struct usb_device *dev,
 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
 		    le16_to_cpu(dev->descriptor.idProduct));
 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
-		goto __err_val;
+		return -ENXIO;
 
-	if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
-		goto __err_val;
+	err = snd_usb_apply_boot_quirk(dev, intf, quirk);
+	if (err < 0)
+		return err;
 
 	/*
 	 * found a config.  now register to ALSA
@@ -508,6 +497,7 @@ snd_usb_audio_probe(struct usb_device *dev,
 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
 			if (usb_chip[i]->shutdown) {
 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
+				err = -EIO;
 				goto __error;
 			}
 			chip = usb_chip[i];
@@ -523,15 +513,16 @@ snd_usb_audio_probe(struct usb_device *dev,
 			if (enable[i] && ! usb_chip[i] &&
 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
-				if (snd_usb_audio_create(intf, dev, i, quirk,
-							 &chip) < 0) {
+				err = snd_usb_audio_create(intf, dev, i, quirk,
+							   &chip);
+				if (err < 0)
 					goto __error;
-				}
 				chip->pm_intf = intf;
 				break;
 			}
 		if (!chip) {
 			dev_err(&dev->dev, "no available usb audio device\n");
+			err = -ENODEV;
 			goto __error;
 		}
 	}
@@ -548,28 +539,32 @@ snd_usb_audio_probe(struct usb_device *dev,
 	err = 1; /* continue */
 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
 		/* need some special handlings */
-		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
+		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
+		if (err < 0)
 			goto __error;
 	}
 
 	if (err > 0) {
 		/* create normal USB audio interfaces */
-		if (snd_usb_create_streams(chip, ifnum) < 0 ||
-		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
+		err = snd_usb_create_streams(chip, ifnum);
+		if (err < 0)
+			goto __error;
+		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
+		if (err < 0)
 			goto __error;
-		}
 	}
 
 	/* we are allowed to call snd_card_register() many times */
-	if (snd_card_register(chip->card) < 0) {
+	err = snd_card_register(chip->card);
+	if (err < 0)
 		goto __error;
-	}
 
 	usb_chip[chip->index] = chip;
 	chip->num_interfaces++;
 	chip->probing = 0;
+	usb_set_intfdata(intf, chip);
 	mutex_unlock(&register_mutex);
-	return chip;
+	return 0;
 
  __error:
 	if (chip) {
@@ -578,17 +573,16 @@ snd_usb_audio_probe(struct usb_device *dev,
 		chip->probing = 0;
 	}
 	mutex_unlock(&register_mutex);
- __err_val:
-	return NULL;
+	return err;
 }
 
 /*
  * we need to take care of counter, since disconnection can be called also
  * many times as well as usb_audio_probe().
  */
-static void snd_usb_audio_disconnect(struct usb_device *dev,
-				     struct snd_usb_audio *chip)
+static void usb_audio_disconnect(struct usb_interface *intf)
 {
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
 	struct snd_card *card;
 	struct list_head *p;
 	bool was_shutdown;
@@ -604,12 +598,14 @@ static void snd_usb_audio_disconnect(struct usb_device *dev,
 
 	mutex_lock(&register_mutex);
 	if (!was_shutdown) {
+		struct snd_usb_stream *as;
 		struct snd_usb_endpoint *ep;
+		struct usb_mixer_interface *mixer;
 
 		snd_card_disconnect(card);
 		/* release the pcm resources */
-		list_for_each(p, &chip->pcm_list) {
-			snd_usb_stream_disconnect(p);
+		list_for_each_entry(as, &chip->pcm_list, list) {
+			snd_usb_stream_disconnect(as);
 		}
 		/* release the endpoint resources */
 		list_for_each_entry(ep, &chip->ep_list, list) {
@@ -620,8 +616,8 @@ static void snd_usb_audio_disconnect(struct usb_device *dev,
 			snd_usbmidi_disconnect(p);
 		}
 		/* release mixer resources */
-		list_for_each(p, &chip->mixer_list) {
-			snd_usb_mixer_disconnect(p);
+		list_for_each_entry(mixer, &chip->mixer_list, list) {
+			snd_usb_mixer_disconnect(mixer);
 		}
 	}
 
@@ -635,27 +631,6 @@ static void snd_usb_audio_disconnect(struct usb_device *dev,
 	}
 }
 
-/*
- * new 2.5 USB kernel API
- */
-static int usb_audio_probe(struct usb_interface *intf,
-			   const struct usb_device_id *id)
-{
-	struct snd_usb_audio *chip;
-	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
-	if (chip) {
-		usb_set_intfdata(intf, chip);
-		return 0;
-	} else
-		return -EIO;
-}
-
-static void usb_audio_disconnect(struct usb_interface *intf)
-{
-	snd_usb_audio_disconnect(interface_to_usbdev(intf),
-				 usb_get_intfdata(intf));
-}
-
 #ifdef CONFIG_PM
 
 int snd_usb_autoresume(struct snd_usb_audio *chip)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 114e3e7ff511..03b074419964 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -348,6 +348,8 @@ static void snd_complete_urb(struct urb *urb)
 {
 	struct snd_urb_ctx *ctx = urb->context;
 	struct snd_usb_endpoint *ep = ctx->ep;
+	struct snd_pcm_substream *substream;
+	unsigned long flags;
 	int err;
 
 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
@@ -364,8 +366,6 @@ static void snd_complete_urb(struct urb *urb)
 			goto exit_clear;
 
 		if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
-			unsigned long flags;
-
 			spin_lock_irqsave(&ep->lock, flags);
 			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
 			spin_unlock_irqrestore(&ep->lock, flags);
@@ -389,7 +389,10 @@ static void snd_complete_urb(struct urb *urb)
 		return;
 
 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
-	//snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+	if (ep->data_subs && ep->data_subs->pcm_substream) {
+		substream = ep->data_subs->pcm_substream;
+		snd_pcm_stop_xrun(substream);
+	}
 
 exit_clear:
 	clear_bit(ctx->index, &ep->active_mask);
@@ -1002,15 +1005,12 @@ void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
 /**
  * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
  *
- * @ep: the list header of the endpoint to free
+ * @ep: the endpoint to free
  *
  * This free all resources of the given ep.
  */
-void snd_usb_endpoint_free(struct list_head *head)
+void snd_usb_endpoint_free(struct snd_usb_endpoint *ep)
 {
-	struct snd_usb_endpoint *ep;
-
-	ep = list_entry(head, struct snd_usb_endpoint, list);
 	kfree(ep);
 }
 
diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
index e61ee5c356a3..6428392d8f62 100644
--- a/sound/usb/endpoint.h
+++ b/sound/usb/endpoint.h
@@ -24,7 +24,7 @@ void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep);
 int  snd_usb_endpoint_activate(struct snd_usb_endpoint *ep);
 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep);
 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep);
-void snd_usb_endpoint_free(struct list_head *head);
+void snd_usb_endpoint_free(struct snd_usb_endpoint *ep);
 
 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep);
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index d3d49525a16b..5bfb695547f8 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -365,6 +365,8 @@ static void snd_usbmidi_error_timer(unsigned long data)
 		if (in && in->error_resubmit) {
 			in->error_resubmit = 0;
 			for (j = 0; j < INPUT_URBS; ++j) {
+				if (atomic_read(&in->urbs[j]->use_count))
+					continue;
 				in->urbs[j]->dev = umidi->dev;
 				snd_usbmidi_submit_urb(in->urbs[j], GFP_ATOMIC);
 			}
diff --git a/sound/usb/misc/ua101.c b/sound/usb/misc/ua101.c
index a1bab149df4d..9581089c28c5 100644
--- a/sound/usb/misc/ua101.c
+++ b/sound/usb/misc/ua101.c
@@ -613,24 +613,14 @@ static int start_usb_playback(struct ua101 *ua)
 
 static void abort_alsa_capture(struct ua101 *ua)
 {
-	unsigned long flags;
-
-	if (test_bit(ALSA_CAPTURE_RUNNING, &ua->states)) {
-		snd_pcm_stream_lock_irqsave(ua->capture.substream, flags);
-		snd_pcm_stop(ua->capture.substream, SNDRV_PCM_STATE_XRUN);
-		snd_pcm_stream_unlock_irqrestore(ua->capture.substream, flags);
-	}
+	if (test_bit(ALSA_CAPTURE_RUNNING, &ua->states))
+		snd_pcm_stop_xrun(ua->capture.substream);
 }
 
 static void abort_alsa_playback(struct ua101 *ua)
 {
-	unsigned long flags;
-
-	if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states)) {
-		snd_pcm_stream_lock_irqsave(ua->playback.substream, flags);
-		snd_pcm_stop(ua->playback.substream, SNDRV_PCM_STATE_XRUN);
-		snd_pcm_stream_unlock_irqrestore(ua->playback.substream, flags);
-	}
+	if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states))
+		snd_pcm_stop_xrun(ua->playback.substream);
 }
 
 static int set_stream_hw(struct ua101 *ua, struct snd_pcm_substream *substream,
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 6e354d326858..41650d5b93b7 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -136,6 +136,10 @@ check_mapped_name(const struct usbmix_name_map *p, char *buf, int buflen)
 	return strlcpy(buf, p->name, buflen);
 }
 
+/* ignore the error value if ignore_ctl_error flag is set */
+#define filter_error(cval, err) \
+	((cval)->head.mixer->ignore_ctl_error ? 0 : (err))
+
 /* check whether the control should be ignored */
 static inline int
 check_ignored_ctl(const struct usbmix_name_map *p)
@@ -286,13 +290,13 @@ static int get_abs_value(struct usb_mixer_elem_info *cval, int val)
 static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request,
 			    int validx, int *value_ret)
 {
-	struct snd_usb_audio *chip = cval->mixer->chip;
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
 	unsigned char buf[2];
 	int val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
 	int timeout = 10;
 	int idx = 0, err;
 
-	err = snd_usb_autoresume(cval->mixer->chip);
+	err = snd_usb_autoresume(chip);
 	if (err < 0)
 		return -EIO;
 
@@ -300,7 +304,7 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request,
 	while (timeout-- > 0) {
 		if (chip->shutdown)
 			break;
-		idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
+		idx = snd_usb_ctrl_intf(chip) | (cval->head.id << 8);
 		if (snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), request,
 				    USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 				    validx, idx, buf, val_len) >= val_len) {
@@ -316,14 +320,14 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request,
 
  out:
 	up_read(&chip->shutdown_rwsem);
-	snd_usb_autosuspend(cval->mixer->chip);
+	snd_usb_autosuspend(chip);
 	return err;
 }
 
 static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request,
 			    int validx, int *value_ret)
 {
-	struct snd_usb_audio *chip = cval->mixer->chip;
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
 	unsigned char buf[2 + 3 * sizeof(__u16)]; /* enough space for one range */
 	unsigned char *val;
 	int idx = 0, ret, size;
@@ -347,7 +351,7 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request,
 	if (chip->shutdown) {
 		ret = -ENODEV;
 	} else {
-		idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
+		idx = snd_usb_ctrl_intf(chip) | (cval->head.id << 8);
 		ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
 			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 			      validx, idx, buf, size);
@@ -392,7 +396,7 @@ static int get_ctl_value(struct usb_mixer_elem_info *cval, int request,
 {
 	validx += cval->idx_off;
 
-	return (cval->mixer->protocol == UAC_VERSION_1) ?
+	return (cval->head.mixer->protocol == UAC_VERSION_1) ?
 		get_ctl_value_v1(cval, request, validx, value_ret) :
 		get_ctl_value_v2(cval, request, validx, value_ret);
 }
@@ -412,7 +416,7 @@ static inline int get_cur_mix_raw(struct usb_mixer_elem_info *cval,
 			     value);
 }
 
-static int get_cur_mix_value(struct usb_mixer_elem_info *cval,
+int snd_usb_get_cur_mix_value(struct usb_mixer_elem_info *cval,
 			     int channel, int index, int *value)
 {
 	int err;
@@ -423,8 +427,8 @@ static int get_cur_mix_value(struct usb_mixer_elem_info *cval,
 	}
 	err = get_cur_mix_raw(cval, channel, value);
 	if (err < 0) {
-		if (!cval->mixer->ignore_ctl_error)
-			usb_audio_dbg(cval->mixer->chip,
+		if (!cval->head.mixer->ignore_ctl_error)
+			usb_audio_dbg(cval->head.mixer->chip,
 				"cannot get current value for control %d ch %d: err = %d\n",
 				      cval->control, channel, err);
 		return err;
@@ -441,13 +445,13 @@ static int get_cur_mix_value(struct usb_mixer_elem_info *cval,
 int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
 				int request, int validx, int value_set)
 {
-	struct snd_usb_audio *chip = cval->mixer->chip;
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
 	unsigned char buf[2];
 	int idx = 0, val_len, err, timeout = 10;
 
 	validx += cval->idx_off;
 
-	if (cval->mixer->protocol == UAC_VERSION_1) {
+	if (cval->head.mixer->protocol == UAC_VERSION_1) {
 		val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
 	} else { /* UAC_VERSION_2 */
 		/* audio class v2 controls are always 2 bytes in size */
@@ -472,7 +476,7 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
 	while (timeout-- > 0) {
 		if (chip->shutdown)
 			break;
-		idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
+		idx = snd_usb_ctrl_intf(chip) | (cval->head.id << 8);
 		if (snd_usb_ctl_msg(chip->dev,
 				    usb_sndctrlpipe(chip->dev, 0), request,
 				    USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
@@ -497,7 +501,7 @@ static int set_cur_ctl_value(struct usb_mixer_elem_info *cval,
 	return snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR, validx, value);
 }
 
-static int set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
+int snd_usb_set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
 			     int index, int value)
 {
 	int err;
@@ -506,7 +510,7 @@ static int set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
 		cval->ch_readonly & (1 << (channel - 1));
 
 	if (read_only) {
-		usb_audio_dbg(cval->mixer->chip,
+		usb_audio_dbg(cval->head.mixer->chip,
 			      "%s(): channel %d of control %d is read_only\n",
 			    __func__, channel, cval->control);
 		return 0;
@@ -565,10 +569,10 @@ static int check_matrix_bitmap(unsigned char *bmap,
  * if failed, give up and free the control instance.
  */
 
-int snd_usb_mixer_add_control(struct usb_mixer_interface *mixer,
+int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
 			      struct snd_kcontrol *kctl)
 {
-	struct usb_mixer_elem_info *cval = kctl->private_data;
+	struct usb_mixer_interface *mixer = list->mixer;
 	int err;
 
 	while (snd_ctl_find_id(mixer->chip->card, &kctl->id))
@@ -578,9 +582,9 @@ int snd_usb_mixer_add_control(struct usb_mixer_interface *mixer,
 			      err);
 		return err;
 	}
-	cval->elem_id = &kctl->id;
-	cval->next_id_elem = mixer->id_elems[cval->id];
-	mixer->id_elems[cval->id] = cval;
+	list->kctl = kctl;
+	list->next_id_elem = mixer->id_elems[list->id];
+	mixer->id_elems[list->id] = list;
 	return 0;
 }
 
@@ -815,7 +819,7 @@ static struct usb_feature_control_info audio_feature_info[] = {
 };
 
 /* private_free callback */
-static void usb_mixer_elem_free(struct snd_kcontrol *kctl)
+void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl)
 {
 	kfree(kctl->private_data);
 	kctl->private_data = NULL;
@@ -829,7 +833,7 @@ static void usb_mixer_elem_free(struct snd_kcontrol *kctl)
 static void volume_control_quirks(struct usb_mixer_elem_info *cval,
 				  struct snd_kcontrol *kctl)
 {
-	struct snd_usb_audio *chip = cval->mixer->chip;
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
 	switch (chip->usb_id) {
 	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
 	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */
@@ -954,10 +958,10 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
 		}
 		if (get_ctl_value(cval, UAC_GET_MAX, (cval->control << 8) | minchn, &cval->max) < 0 ||
 		    get_ctl_value(cval, UAC_GET_MIN, (cval->control << 8) | minchn, &cval->min) < 0) {
-			usb_audio_err(cval->mixer->chip,
+			usb_audio_err(cval->head.mixer->chip,
 				      "%d:%d: cannot get min/max values for control %d (id %d)\n",
-				   cval->id, snd_usb_ctrl_intf(cval->mixer->chip),
-							       cval->control, cval->id);
+				   cval->head.id, snd_usb_ctrl_intf(cval->head.mixer->chip),
+							       cval->control, cval->head.id);
 			return -EINVAL;
 		}
 		if (get_ctl_value(cval, UAC_GET_RES,
@@ -998,7 +1002,7 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
 				else
 					test -= cval->res;
 				if (test < cval->min || test > cval->max ||
-				    set_cur_mix_value(cval, minchn, 0, test) ||
+				    snd_usb_set_cur_mix_value(cval, minchn, 0, test) ||
 				    get_cur_mix_raw(cval, minchn, &check)) {
 					cval->res = last_valid_res;
 					break;
@@ -1007,7 +1011,7 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
 					break;
 				cval->res *= 2;
 			}
-			set_cur_mix_value(cval, minchn, 0, saved);
+			snd_usb_set_cur_mix_value(cval, minchn, 0, saved);
 		}
 
 		cval->initialized = 1;
@@ -1061,7 +1065,7 @@ static int mixer_ctl_feature_info(struct snd_kcontrol *kcontrol,
 				kcontrol->vd[0].access &= 
 					~(SNDRV_CTL_ELEM_ACCESS_TLV_READ |
 					  SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
-				snd_ctl_notify(cval->mixer->chip->card,
+				snd_ctl_notify(cval->head.mixer->chip->card,
 					       SNDRV_CTL_EVENT_MASK_INFO,
 					       &kcontrol->id);
 			}
@@ -1086,9 +1090,9 @@ static int mixer_ctl_feature_get(struct snd_kcontrol *kcontrol,
 		for (c = 0; c < MAX_CHANNELS; c++) {
 			if (!(cval->cmask & (1 << c)))
 				continue;
-			err = get_cur_mix_value(cval, c + 1, cnt, &val);
+			err = snd_usb_get_cur_mix_value(cval, c + 1, cnt, &val);
 			if (err < 0)
-				return cval->mixer->ignore_ctl_error ? 0 : err;
+				return filter_error(cval, err);
 			val = get_relative_value(cval, val);
 			ucontrol->value.integer.value[cnt] = val;
 			cnt++;
@@ -1096,9 +1100,9 @@ static int mixer_ctl_feature_get(struct snd_kcontrol *kcontrol,
 		return 0;
 	} else {
 		/* master channel */
-		err = get_cur_mix_value(cval, 0, 0, &val);
+		err = snd_usb_get_cur_mix_value(cval, 0, 0, &val);
 		if (err < 0)
-			return cval->mixer->ignore_ctl_error ? 0 : err;
+			return filter_error(cval, err);
 		val = get_relative_value(cval, val);
 		ucontrol->value.integer.value[0] = val;
 	}
@@ -1118,26 +1122,26 @@ static int mixer_ctl_feature_put(struct snd_kcontrol *kcontrol,
 		for (c = 0; c < MAX_CHANNELS; c++) {
 			if (!(cval->cmask & (1 << c)))
 				continue;
-			err = get_cur_mix_value(cval, c + 1, cnt, &oval);
+			err = snd_usb_get_cur_mix_value(cval, c + 1, cnt, &oval);
 			if (err < 0)
-				return cval->mixer->ignore_ctl_error ? 0 : err;
+				return filter_error(cval, err);
 			val = ucontrol->value.integer.value[cnt];
 			val = get_abs_value(cval, val);
 			if (oval != val) {
-				set_cur_mix_value(cval, c + 1, cnt, val);
+				snd_usb_set_cur_mix_value(cval, c + 1, cnt, val);
 				changed = 1;
 			}
 			cnt++;
 		}
 	} else {
 		/* master channel */
-		err = get_cur_mix_value(cval, 0, 0, &oval);
+		err = snd_usb_get_cur_mix_value(cval, 0, 0, &oval);
 		if (err < 0)
-			return cval->mixer->ignore_ctl_error ? 0 : err;
+			return filter_error(cval, err);
 		val = ucontrol->value.integer.value[0];
 		val = get_abs_value(cval, val);
 		if (val != oval) {
-			set_cur_mix_value(cval, 0, 0, val);
+			snd_usb_set_cur_mix_value(cval, 0, 0, val);
 			changed = 1;
 		}
 	}
@@ -1231,8 +1235,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
 	cval = kzalloc(sizeof(*cval), GFP_KERNEL);
 	if (!cval)
 		return;
-	cval->mixer = state->mixer;
-	cval->id = unitid;
+	snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
 	cval->control = control;
 	cval->cmask = ctl_mask;
 	cval->val_type = audio_feature_info[control-1].type;
@@ -1250,7 +1253,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
 
 	/*
 	 * If all channels in the mask are marked read-only, make the control
-	 * read-only. set_cur_mix_value() will check the mask again and won't
+	 * read-only. snd_usb_set_cur_mix_value() will check the mask again and won't
 	 * issue write commands to read-only channels.
 	 */
 	if (cval->channels == readonly_mask)
@@ -1263,7 +1266,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
 		kfree(cval);
 		return;
 	}
-	kctl->private_free = usb_mixer_elem_free;
+	kctl->private_free = snd_usb_mixer_elem_free;
 
 	len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
 	mapped_name = len != 0;
@@ -1290,9 +1293,8 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
 						    kctl->id.name,
 						    sizeof(kctl->id.name), 1);
 			if (!len)
-				len = snprintf(kctl->id.name,
-					       sizeof(kctl->id.name),
-					       "Feature %d", unitid);
+				snprintf(kctl->id.name, sizeof(kctl->id.name),
+					 "Feature %d", unitid);
 		}
 
 		if (!mapped_name)
@@ -1305,9 +1307,9 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
 		 */
 		if (!mapped_name && !(state->oterm.type >> 16)) {
 			if ((state->oterm.type & 0xff00) == 0x0100)
-				len = append_ctl_name(kctl, " Capture");
+				append_ctl_name(kctl, " Capture");
 			else
-				len = append_ctl_name(kctl, " Playback");
+				append_ctl_name(kctl, " Playback");
 		}
 		append_ctl_name(kctl, control == UAC_FU_MUTE ?
 				" Switch" : " Volume");
@@ -1344,14 +1346,14 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
 			       range);
 		usb_audio_warn(state->chip,
 			       "[%d] FU [%s] ch = %d, val = %d/%d/%d",
-			       cval->id, kctl->id.name, cval->channels,
+			       cval->head.id, kctl->id.name, cval->channels,
 			       cval->min, cval->max, cval->res);
 	}
 
 	usb_audio_dbg(state->chip, "[%d] FU [%s] ch = %d, val = %d/%d/%d\n",
-		      cval->id, kctl->id.name, cval->channels,
+		      cval->head.id, kctl->id.name, cval->channels,
 		      cval->min, cval->max, cval->res);
-	snd_usb_mixer_add_control(state->mixer, kctl);
+	snd_usb_mixer_add_control(&cval->head, kctl);
 }
 
 /*
@@ -1525,8 +1527,7 @@ static void build_mixer_unit_ctl(struct mixer_build *state,
 	if (!cval)
 		return;
 
-	cval->mixer = state->mixer;
-	cval->id = unitid;
+	snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
 	cval->control = in_ch + 1; /* based on 1 */
 	cval->val_type = USB_MIXER_S16;
 	for (i = 0; i < num_outs; i++) {
@@ -1547,7 +1548,7 @@ static void build_mixer_unit_ctl(struct mixer_build *state,
 		kfree(cval);
 		return;
 	}
-	kctl->private_free = usb_mixer_elem_free;
+	kctl->private_free = snd_usb_mixer_elem_free;
 
 	len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
 	if (!len)
@@ -1558,8 +1559,8 @@ static void build_mixer_unit_ctl(struct mixer_build *state,
 	append_ctl_name(kctl, " Volume");
 
 	usb_audio_dbg(state->chip, "[%d] MU [%s] ch = %d, val = %d/%d\n",
-		    cval->id, kctl->id.name, cval->channels, cval->min, cval->max);
-	snd_usb_mixer_add_control(state->mixer, kctl);
+		    cval->head.id, kctl->id.name, cval->channels, cval->min, cval->max);
+	snd_usb_mixer_add_control(&cval->head, kctl);
 }
 
 /*
@@ -1629,12 +1630,10 @@ static int mixer_ctl_procunit_get(struct snd_kcontrol *kcontrol,
 	int err, val;
 
 	err = get_cur_ctl_value(cval, cval->control << 8, &val);
-	if (err < 0 && cval->mixer->ignore_ctl_error) {
+	if (err < 0) {
 		ucontrol->value.integer.value[0] = cval->min;
-		return 0;
+		return filter_error(cval, err);
 	}
-	if (err < 0)
-		return err;
 	val = get_relative_value(cval, val);
 	ucontrol->value.integer.value[0] = val;
 	return 0;
@@ -1648,11 +1647,8 @@ static int mixer_ctl_procunit_put(struct snd_kcontrol *kcontrol,
 	int val, oval, err;
 
 	err = get_cur_ctl_value(cval, cval->control << 8, &oval);
-	if (err < 0) {
-		if (cval->mixer->ignore_ctl_error)
-			return 0;
-		return err;
-	}
+	if (err < 0)
+		return filter_error(cval, err);
 	val = ucontrol->value.integer.value[0];
 	val = get_abs_value(cval, val);
 	if (val != oval) {
@@ -1814,8 +1810,7 @@ static int build_audio_procunit(struct mixer_build *state, int unitid,
 		cval = kzalloc(sizeof(*cval), GFP_KERNEL);
 		if (!cval)
 			return -ENOMEM;
-		cval->mixer = state->mixer;
-		cval->id = unitid;
+		snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
 		cval->control = valinfo->control;
 		cval->val_type = valinfo->val_type;
 		cval->channels = 1;
@@ -1847,7 +1842,7 @@ static int build_audio_procunit(struct mixer_build *state, int unitid,
 			kfree(cval);
 			return -ENOMEM;
 		}
-		kctl->private_free = usb_mixer_elem_free;
+		kctl->private_free = snd_usb_mixer_elem_free;
 
 		if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name))) {
 			/* nothing */ ;
@@ -1868,10 +1863,10 @@ static int build_audio_procunit(struct mixer_build *state, int unitid,
 
 		usb_audio_dbg(state->chip,
 			      "[%d] PU [%s] ch = %d, val = %d/%d\n",
-			      cval->id, kctl->id.name, cval->channels,
+			      cval->head.id, kctl->id.name, cval->channels,
 			      cval->min, cval->max);
 
-		err = snd_usb_mixer_add_control(state->mixer, kctl);
+		err = snd_usb_mixer_add_control(&cval->head, kctl);
 		if (err < 0)
 			return err;
 	}
@@ -1924,11 +1919,8 @@ static int mixer_ctl_selector_get(struct snd_kcontrol *kcontrol,
 
 	err = get_cur_ctl_value(cval, cval->control << 8, &val);
 	if (err < 0) {
-		if (cval->mixer->ignore_ctl_error) {
-			ucontrol->value.enumerated.item[0] = 0;
-			return 0;
-		}
-		return err;
+		ucontrol->value.enumerated.item[0] = 0;
+		return filter_error(cval, err);
 	}
 	val = get_relative_value(cval, val);
 	ucontrol->value.enumerated.item[0] = val;
@@ -1943,11 +1935,8 @@ static int mixer_ctl_selector_put(struct snd_kcontrol *kcontrol,
 	int val, oval, err;
 
 	err = get_cur_ctl_value(cval, cval->control << 8, &oval);
-	if (err < 0) {
-		if (cval->mixer->ignore_ctl_error)
-			return 0;
-		return err;
-	}
+	if (err < 0)
+		return filter_error(cval, err);
 	val = ucontrol->value.enumerated.item[0];
 	val = get_abs_value(cval, val);
 	if (val != oval) {
@@ -2024,8 +2013,7 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	cval = kzalloc(sizeof(*cval), GFP_KERNEL);
 	if (!cval)
 		return -ENOMEM;
-	cval->mixer = state->mixer;
-	cval->id = unitid;
+	snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
 	cval->val_type = USB_MIXER_U8;
 	cval->channels = 1;
 	cval->min = 1;
@@ -2096,11 +2084,8 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	}
 
 	usb_audio_dbg(state->chip, "[%d] SU [%s] items = %d\n",
-		    cval->id, kctl->id.name, desc->bNrInPins);
-	if ((err = snd_usb_mixer_add_control(state->mixer, kctl)) < 0)
-		return err;
-
-	return 0;
+		    cval->head.id, kctl->id.name, desc->bNrInPins);
+	return snd_usb_mixer_add_control(&cval->head, kctl);
 }
 
 /*
@@ -2245,25 +2230,21 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 
 void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid)
 {
-	struct usb_mixer_elem_info *info;
+	struct usb_mixer_elem_list *list;
 
-	for (info = mixer->id_elems[unitid]; info; info = info->next_id_elem)
+	for (list = mixer->id_elems[unitid]; list; list = list->next_id_elem)
 		snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
-			       info->elem_id);
+			       &list->kctl->id);
 }
 
 static void snd_usb_mixer_dump_cval(struct snd_info_buffer *buffer,
-				    int unitid,
-				    struct usb_mixer_elem_info *cval)
+				    struct usb_mixer_elem_list *list)
 {
+	struct usb_mixer_elem_info *cval = (struct usb_mixer_elem_info *)list;
 	static char *val_types[] = {"BOOLEAN", "INV_BOOLEAN",
 				    "S8", "U8", "S16", "U16"};
-	snd_iprintf(buffer, "  Unit: %i\n", unitid);
-	if (cval->elem_id)
-		snd_iprintf(buffer, "    Control: name=\"%s\", index=%i\n",
-				cval->elem_id->name, cval->elem_id->index);
 	snd_iprintf(buffer, "    Info: id=%i, control=%i, cmask=0x%x, "
-			    "channels=%i, type=\"%s\"\n", cval->id,
+			    "channels=%i, type=\"%s\"\n", cval->head.id,
 			    cval->control, cval->cmask, cval->channels,
 			    val_types[cval->val_type]);
 	snd_iprintf(buffer, "    Volume: min=%i, max=%i, dBmin=%i, dBmax=%i\n",
@@ -2275,7 +2256,7 @@ static void snd_usb_mixer_proc_read(struct snd_info_entry *entry,
 {
 	struct snd_usb_audio *chip = entry->private_data;
 	struct usb_mixer_interface *mixer;
-	struct usb_mixer_elem_info *cval;
+	struct usb_mixer_elem_list *list;
 	int unitid;
 
 	list_for_each_entry(mixer, &chip->mixer_list, list) {
@@ -2285,9 +2266,17 @@ static void snd_usb_mixer_proc_read(struct snd_info_entry *entry,
 				mixer->ignore_ctl_error);
 		snd_iprintf(buffer, "Card: %s\n", chip->card->longname);
 		for (unitid = 0; unitid < MAX_ID_ELEMS; unitid++) {
-			for (cval = mixer->id_elems[unitid]; cval;
-						cval = cval->next_id_elem)
-				snd_usb_mixer_dump_cval(buffer, unitid, cval);
+			for (list = mixer->id_elems[unitid]; list;
+			     list = list->next_id_elem) {
+				snd_iprintf(buffer, "  Unit: %i\n", list->id);
+				if (list->kctl)
+					snd_iprintf(buffer,
+						    "    Control: name=\"%s\", index=%i\n",
+						    list->kctl->id.name,
+						    list->kctl->id.index);
+				if (list->dump)
+					list->dump(buffer, list);
+			}
 		}
 	}
 }
@@ -2295,7 +2284,7 @@ static void snd_usb_mixer_proc_read(struct snd_info_entry *entry,
 static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
 				       int attribute, int value, int index)
 {
-	struct usb_mixer_elem_info *info;
+	struct usb_mixer_elem_list *list;
 	__u8 unitid = (index >> 8) & 0xff;
 	__u8 control = (value >> 8) & 0xff;
 	__u8 channel = value & 0xff;
@@ -2307,7 +2296,13 @@ static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
 		return;
 	}
 
-	for (info = mixer->id_elems[unitid]; info; info = info->next_id_elem) {
+	for (list = mixer->id_elems[unitid]; list; list = list->next_id_elem) {
+		struct usb_mixer_elem_info *info;
+
+		if (!list->kctl)
+			continue;
+
+		info = (struct usb_mixer_elem_info *)list;
 		if (info->control != control)
 			continue;
 
@@ -2320,7 +2315,7 @@ static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
 				info->cached = 0;
 
 			snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
-					info->elem_id);
+				       &info->head.kctl->id);
 			break;
 
 		case UAC2_CS_RANGE:
@@ -2485,11 +2480,8 @@ _error:
 	return err;
 }
 
-void snd_usb_mixer_disconnect(struct list_head *p)
+void snd_usb_mixer_disconnect(struct usb_mixer_interface *mixer)
 {
-	struct usb_mixer_interface *mixer;
-
-	mixer = list_entry(p, struct usb_mixer_interface, list);
 	usb_kill_urb(mixer->urb);
 	usb_kill_urb(mixer->rc_urb);
 }
@@ -2521,8 +2513,9 @@ int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer)
 	return 0;
 }
 
-static int restore_mixer_value(struct usb_mixer_elem_info *cval)
+static int restore_mixer_value(struct usb_mixer_elem_list *list)
 {
+	struct usb_mixer_elem_info *cval = (struct usb_mixer_elem_info *)list;
 	int c, err, idx;
 
 	if (cval->cmask) {
@@ -2531,7 +2524,7 @@ static int restore_mixer_value(struct usb_mixer_elem_info *cval)
 			if (!(cval->cmask & (1 << c)))
 				continue;
 			if (cval->cached & (1 << c)) {
-				err = set_cur_mix_value(cval, c + 1, idx,
+				err = snd_usb_set_cur_mix_value(cval, c + 1, idx,
 							cval->cache_val[idx]);
 				if (err < 0)
 					return err;
@@ -2541,7 +2534,7 @@ static int restore_mixer_value(struct usb_mixer_elem_info *cval)
 	} else {
 		/* master */
 		if (cval->cached) {
-			err = set_cur_mix_value(cval, 0, 0, *cval->cache_val);
+			err = snd_usb_set_cur_mix_value(cval, 0, 0, *cval->cache_val);
 			if (err < 0)
 				return err;
 		}
@@ -2552,19 +2545,19 @@ static int restore_mixer_value(struct usb_mixer_elem_info *cval)
 
 int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume)
 {
-	struct usb_mixer_elem_info *cval;
+	struct usb_mixer_elem_list *list;
 	int id, err;
 
-	/* FIXME: any mixer quirks? */
-
 	if (reset_resume) {
 		/* restore cached mixer values */
 		for (id = 0; id < MAX_ID_ELEMS; id++) {
-			for (cval = mixer->id_elems[id]; cval;
-			     cval = cval->next_id_elem) {
-				err = restore_mixer_value(cval);
-				if (err < 0)
-					return err;
+			for (list = mixer->id_elems[id]; list;
+			     list = list->next_id_elem) {
+				if (list->resume) {
+					err = list->resume(list);
+					if (err < 0)
+						return err;
+				}
 			}
 		}
 	}
@@ -2572,3 +2565,15 @@ int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume)
 	return snd_usb_mixer_activate(mixer);
 }
 #endif
+
+void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
+				 struct usb_mixer_interface *mixer,
+				 int unitid)
+{
+	list->mixer = mixer;
+	list->id = unitid;
+	list->dump = snd_usb_mixer_dump_cval;
+#ifdef CONFIG_PM
+	list->resume = restore_mixer_value;
+#endif
+}
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
index 73b1f649447b..d3268f0ee2b3 100644
--- a/sound/usb/mixer.h
+++ b/sound/usb/mixer.h
@@ -1,6 +1,8 @@
 #ifndef __USBMIXER_H
 #define __USBMIXER_H
 
+#include <sound/info.h>
+
 struct usb_mixer_interface {
 	struct snd_usb_audio *chip;
 	struct usb_host_interface *hostif;
@@ -8,7 +10,7 @@ struct usb_mixer_interface {
 	unsigned int ignore_ctl_error;
 	struct urb *urb;
 	/* array[MAX_ID_ELEMS], indexed by unit id */
-	struct usb_mixer_elem_info **id_elems;
+	struct usb_mixer_elem_list **id_elems;
 
 	/* the usb audio specification version this interface complies to */
 	int protocol;
@@ -20,9 +22,6 @@ struct usb_mixer_interface {
 	struct urb *rc_urb;
 	struct usb_ctrlrequest *rc_setup_packet;
 	u8 rc_buffer[6];
-
-	u8 audigy2nx_leds[3];
-	u8 xonar_u1_status;
 };
 
 #define MAX_CHANNELS	16	/* max logical channels */
@@ -36,11 +35,21 @@ enum {
 	USB_MIXER_U16,
 };
 
-struct usb_mixer_elem_info {
+typedef void (*usb_mixer_elem_dump_func_t)(struct snd_info_buffer *buffer,
+					 struct usb_mixer_elem_list *list);
+typedef int (*usb_mixer_elem_resume_func_t)(struct usb_mixer_elem_list *elem);
+
+struct usb_mixer_elem_list {
 	struct usb_mixer_interface *mixer;
-	struct usb_mixer_elem_info *next_id_elem; /* list of controls with same id */
-	struct snd_ctl_elem_id *elem_id;
+	struct usb_mixer_elem_list *next_id_elem; /* list of controls with same id */
+	struct snd_kcontrol *kctl;
 	unsigned int id;
+	usb_mixer_elem_dump_func_t dump;
+	usb_mixer_elem_resume_func_t resume;
+};
+
+struct usb_mixer_elem_info {
+	struct usb_mixer_elem_list head;
 	unsigned int control;	/* CS or ICN (high byte) */
 	unsigned int cmask; /* channel mask bitmap: 0 = master */
 	unsigned int idx_off; /* Control index offset */
@@ -53,20 +62,25 @@ struct usb_mixer_elem_info {
 	int cached;
 	int cache_val[MAX_CHANNELS];
 	u8 initialized;
+	void *private_data;
 };
 
 int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
 			 int ignore_error);
-void snd_usb_mixer_disconnect(struct list_head *p);
+void snd_usb_mixer_disconnect(struct usb_mixer_interface *mixer);
 
 void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid);
 
 int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
 				int request, int validx, int value_set);
 
-int snd_usb_mixer_add_control(struct usb_mixer_interface *mixer,
+int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
 			      struct snd_kcontrol *kctl);
 
+void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
+				 struct usb_mixer_interface *mixer,
+				 int unitid);
+
 int snd_usb_mixer_vol_tlv(struct snd_kcontrol *kcontrol, int op_flag,
 			  unsigned int size, unsigned int __user *_tlv);
 
@@ -75,4 +89,12 @@ int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer);
 int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume);
 #endif
 
+int snd_usb_set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
+                             int index, int value);
+
+int snd_usb_get_cur_mix_value(struct usb_mixer_elem_info *cval,
+                             int channel, int index, int *value);
+
+extern void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl);
+
 #endif /* __USBMIXER_H */
diff --git a/sound/usb/mixer_maps.c b/sound/usb/mixer_maps.c
index d1d72ff50347..1994d41348f8 100644
--- a/sound/usb/mixer_maps.c
+++ b/sound/usb/mixer_maps.c
@@ -179,6 +179,11 @@ static struct usbmix_name_map audigy2nx_map[] = {
 	{ 0 } /* terminator */
 };
 
+static struct usbmix_name_map mbox1_map[] = {
+	{ 1, "Clock" },
+	{ 0 } /* terminator */
+};
+
 static struct usbmix_selector_map c400_selectors[] = {
 	{
 		.id = 0x80,
@@ -416,6 +421,10 @@ static struct usbmix_ctl_map usbmix_ctl_maps[] = {
 		.map = aureon_51_2_map,
 	},
 	{
+		.id = USB_ID(0x0dba, 0x1000),
+		.map = mbox1_map,
+	},
+	{
 		.id = USB_ID(0x13e5, 0x0001),
 		.map = scratch_live_map,
 		.ignore_ctl_error = 1,
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 8c9bf4b7aaf0..dc9df007d3e3 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -41,6 +41,7 @@
 #include "usbaudio.h"
 #include "mixer.h"
 #include "mixer_quirks.h"
+#include "mixer_scarlett.h"
 #include "helper.h"
 
 extern struct snd_kcontrol_new *snd_usb_feature_unit_ctl;
@@ -52,13 +53,6 @@ struct std_mono_table {
 	snd_kcontrol_tlv_rw_t *tlv_callback;
 };
 
-/* private_free callback */
-static void usb_mixer_elem_free(struct snd_kcontrol *kctl)
-{
-	kfree(kctl->private_data);
-	kctl->private_data = NULL;
-}
-
 /* This function allows for the creation of standard UAC controls.
  * See the quirks for M-Audio FTUs or Ebox-44.
  * If you don't want to set a TLV callback pass NULL.
@@ -75,7 +69,6 @@ static int snd_create_std_mono_ctl_offset(struct usb_mixer_interface *mixer,
 				const char *name,
 				snd_kcontrol_tlv_rw_t *tlv_callback)
 {
-	int err;
 	struct usb_mixer_elem_info *cval;
 	struct snd_kcontrol *kctl;
 
@@ -83,8 +76,7 @@ static int snd_create_std_mono_ctl_offset(struct usb_mixer_interface *mixer,
 	if (!cval)
 		return -ENOMEM;
 
-	cval->id = unitid;
-	cval->mixer = mixer;
+	snd_usb_mixer_elem_init_std(&cval->head, mixer, unitid);
 	cval->val_type = val_type;
 	cval->channels = 1;
 	cval->control = control;
@@ -108,7 +100,7 @@ static int snd_create_std_mono_ctl_offset(struct usb_mixer_interface *mixer,
 
 	/* Set name */
 	snprintf(kctl->id.name, sizeof(kctl->id.name), name);
-	kctl->private_free = usb_mixer_elem_free;
+	kctl->private_free = snd_usb_mixer_elem_free;
 
 	/* set TLV */
 	if (tlv_callback) {
@@ -118,11 +110,7 @@ static int snd_create_std_mono_ctl_offset(struct usb_mixer_interface *mixer,
 			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
 	}
 	/* Add control to mixer */
-	err = snd_usb_mixer_add_control(mixer, kctl);
-	if (err < 0)
-		return err;
-
-	return 0;
+	return snd_usb_mixer_add_control(&cval->head, kctl);
 }
 
 static int snd_create_std_mono_ctl(struct usb_mixer_interface *mixer,
@@ -156,6 +144,32 @@ static int snd_create_std_mono_table(struct usb_mixer_interface *mixer,
 	return 0;
 }
 
+static int add_single_ctl_with_resume(struct usb_mixer_interface *mixer,
+				      int id,
+				      usb_mixer_elem_resume_func_t resume,
+				      const struct snd_kcontrol_new *knew,
+				      struct usb_mixer_elem_list **listp)
+{
+	struct usb_mixer_elem_list *list;
+	struct snd_kcontrol *kctl;
+
+	list = kzalloc(sizeof(*list), GFP_KERNEL);
+	if (!list)
+		return -ENOMEM;
+	if (listp)
+		*listp = list;
+	list->mixer = mixer;
+	list->id = id;
+	list->resume = resume;
+	kctl = snd_ctl_new1(knew, list);
+	if (!kctl) {
+		kfree(list);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+	return snd_usb_mixer_add_control(list, kctl);
+}
+
 /*
  * Sound Blaster remote control configuration
  *
@@ -283,84 +297,90 @@ static int snd_usb_soundblaster_remote_init(struct usb_mixer_interface *mixer)
 
 static int snd_audigy2nx_led_get(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
-	int index = kcontrol->private_value;
-
-	ucontrol->value.integer.value[0] = mixer->audigy2nx_leds[index];
+	ucontrol->value.integer.value[0] = kcontrol->private_value >> 8;
 	return 0;
 }
 
-static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
+static int snd_audigy2nx_led_update(struct usb_mixer_interface *mixer,
+				    int value, int index)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
-	int index = kcontrol->private_value;
-	int value = ucontrol->value.integer.value[0];
-	int err, changed;
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
 
-	if (value > 1)
-		return -EINVAL;
-	changed = value != mixer->audigy2nx_leds[index];
-	down_read(&mixer->chip->shutdown_rwsem);
-	if (mixer->chip->shutdown) {
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown) {
 		err = -ENODEV;
 		goto out;
 	}
-	if (mixer->chip->usb_id == USB_ID(0x041e, 0x3042))
-		err = snd_usb_ctl_msg(mixer->chip->dev,
-			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
+	if (chip->usb_id == USB_ID(0x041e, 0x3042))
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x24,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      !value, 0, NULL, 0);
 	/* USB X-Fi S51 Pro */
-	if (mixer->chip->usb_id == USB_ID(0x041e, 0x30df))
-		err = snd_usb_ctl_msg(mixer->chip->dev,
-			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
+	if (chip->usb_id == USB_ID(0x041e, 0x30df))
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x24,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      !value, 0, NULL, 0);
 	else
-		err = snd_usb_ctl_msg(mixer->chip->dev,
-			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x24,
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x24,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			      value, index + 2, NULL, 0);
  out:
-	up_read(&mixer->chip->shutdown_rwsem);
-	if (err < 0)
-		return err;
-	mixer->audigy2nx_leds[index] = value;
-	return changed;
+	up_read(&chip->shutdown_rwsem);
+	return err;
 }
 
-static struct snd_kcontrol_new snd_audigy2nx_controls[] = {
-	{
-		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
-		.name = "CMSS LED Switch",
-		.info = snd_audigy2nx_led_info,
-		.get = snd_audigy2nx_led_get,
-		.put = snd_audigy2nx_led_put,
-		.private_value = 0,
-	},
-	{
-		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
-		.name = "Power LED Switch",
-		.info = snd_audigy2nx_led_info,
-		.get = snd_audigy2nx_led_get,
-		.put = snd_audigy2nx_led_put,
-		.private_value = 1,
-	},
-	{
-		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
-		.name = "Dolby Digital LED Switch",
-		.info = snd_audigy2nx_led_info,
-		.get = snd_audigy2nx_led_get,
-		.put = snd_audigy2nx_led_put,
-		.private_value = 2,
-	},
+static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int index = kcontrol->private_value & 0xff;
+	int value = ucontrol->value.integer.value[0];
+	int old_value = kcontrol->private_value >> 8;
+	int err;
+
+	if (value > 1)
+		return -EINVAL;
+	if (value == old_value)
+		return 0;
+	kcontrol->private_value = (value << 8) | index;
+	err = snd_audigy2nx_led_update(mixer, value, index);
+	return err < 0 ? err : 1;
+}
+
+static int snd_audigy2nx_led_resume(struct usb_mixer_elem_list *list)
+{
+	int priv_value = list->kctl->private_value;
+
+	return snd_audigy2nx_led_update(list->mixer, priv_value >> 8,
+					priv_value & 0xff);
+}
+
+/* name and private_value are set dynamically */
+static struct snd_kcontrol_new snd_audigy2nx_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.info = snd_audigy2nx_led_info,
+	.get = snd_audigy2nx_led_get,
+	.put = snd_audigy2nx_led_put,
+};
+
+static const char * const snd_audigy2nx_led_names[] = {
+	"CMSS LED Switch",
+	"Power LED Switch",
+	"Dolby Digital LED Switch",
 };
 
 static int snd_audigy2nx_controls_create(struct usb_mixer_interface *mixer)
 {
 	int i, err;
 
-	for (i = 0; i < ARRAY_SIZE(snd_audigy2nx_controls); ++i) {
+	for (i = 0; i < ARRAY_SIZE(snd_audigy2nx_led_names); ++i) {
+		struct snd_kcontrol_new knew;
+
 		/* USB X-Fi S51 doesn't have a CMSS LED */
 		if ((mixer->chip->usb_id == USB_ID(0x041e, 0x3042)) && i == 0)
 			continue;
@@ -373,12 +393,16 @@ static int snd_audigy2nx_controls_create(struct usb_mixer_interface *mixer)
 			 mixer->chip->usb_id == USB_ID(0x041e, 0x30df) ||
 			 mixer->chip->usb_id == USB_ID(0x041e, 0x3048)))
 			break; 
-		err = snd_ctl_add(mixer->chip->card,
-				  snd_ctl_new1(&snd_audigy2nx_controls[i], mixer));
+
+		knew = snd_audigy2nx_control;
+		knew.name = snd_audigy2nx_led_names[i];
+		knew.private_value = (1 << 8) | i; /* LED on as default */
+		err = add_single_ctl_with_resume(mixer, 0,
+						 snd_audigy2nx_led_resume,
+						 &knew, NULL);
 		if (err < 0)
 			return err;
 	}
-	mixer->audigy2nx_leds[1] = 1; /* Power LED is on by default */
 	return 0;
 }
 
@@ -437,19 +461,9 @@ static void snd_audigy2nx_proc_read(struct snd_info_entry *entry,
 static int snd_emu0204_ch_switch_info(struct snd_kcontrol *kcontrol,
 				      struct snd_ctl_elem_info *uinfo)
 {
-	static const char *texts[2] = {"1/2",
-				       "3/4"
-	};
+	static const char * const texts[2] = {"1/2", "3/4"};
 
-	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
-	uinfo->count = 1;
-	uinfo->value.enumerated.items = 2;
-	if (uinfo->value.enumerated.item > 1)
-		uinfo->value.enumerated.item = 1;
-	strcpy(uinfo->value.enumerated.name,
-		texts[uinfo->value.enumerated.item]);
-
-	return 0;
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
 }
 
 static int snd_emu0204_ch_switch_get(struct snd_kcontrol *kcontrol,
@@ -459,100 +473,122 @@ static int snd_emu0204_ch_switch_get(struct snd_kcontrol *kcontrol,
 	return 0;
 }
 
-static int snd_emu0204_ch_switch_put(struct snd_kcontrol *kcontrol,
-				     struct snd_ctl_elem_value *ucontrol)
+static int snd_emu0204_ch_switch_update(struct usb_mixer_interface *mixer,
+					int value)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
-	unsigned int value = ucontrol->value.enumerated.item[0];
-	int err, changed;
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
 	unsigned char buf[2];
 
-	if (value > 1)
-		return -EINVAL;
-
-	buf[0] = 0x01;
-	buf[1] = value ? 0x02 : 0x01;
-
-	changed = value != kcontrol->private_value;
-	down_read(&mixer->chip->shutdown_rwsem);
+	down_read(&chip->shutdown_rwsem);
 	if (mixer->chip->shutdown) {
 		err = -ENODEV;
 		goto out;
 	}
-	err = snd_usb_ctl_msg(mixer->chip->dev,
-		      usb_sndctrlpipe(mixer->chip->dev, 0), UAC_SET_CUR,
+
+	buf[0] = 0x01;
+	buf[1] = value ? 0x02 : 0x01;
+	err = snd_usb_ctl_msg(chip->dev,
+		      usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
 		      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
 		      0x0400, 0x0e00, buf, 2);
  out:
-	up_read(&mixer->chip->shutdown_rwsem);
-	if (err < 0)
-		return err;
+	up_read(&chip->shutdown_rwsem);
+	return err;
+}
+
+static int snd_emu0204_ch_switch_put(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+	unsigned int value = ucontrol->value.enumerated.item[0];
+	int err;
+
+	if (value > 1)
+		return -EINVAL;
+
+	if (value == kcontrol->private_value)
+		return 0;
+
 	kcontrol->private_value = value;
-	return changed;
+	err = snd_emu0204_ch_switch_update(mixer, value);
+	return err < 0 ? err : 1;
 }
 
+static int snd_emu0204_ch_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_emu0204_ch_switch_update(list->mixer,
+					    list->kctl->private_value);
+}
 
-static struct snd_kcontrol_new snd_emu0204_controls[] = {
-	{
-		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
-		.name = "Front Jack Channels",
-		.info = snd_emu0204_ch_switch_info,
-		.get = snd_emu0204_ch_switch_get,
-		.put = snd_emu0204_ch_switch_put,
-		.private_value = 0,
-	},
+static struct snd_kcontrol_new snd_emu0204_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Front Jack Channels",
+	.info = snd_emu0204_ch_switch_info,
+	.get = snd_emu0204_ch_switch_get,
+	.put = snd_emu0204_ch_switch_put,
+	.private_value = 0,
 };
 
 static int snd_emu0204_controls_create(struct usb_mixer_interface *mixer)
 {
-	int i, err;
-
-	for (i = 0; i < ARRAY_SIZE(snd_emu0204_controls); ++i) {
-		err = snd_ctl_add(mixer->chip->card,
-			snd_ctl_new1(&snd_emu0204_controls[i], mixer));
-		if (err < 0)
-			return err;
-	}
-
-	return 0;
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_emu0204_ch_switch_resume,
+					  &snd_emu0204_control, NULL);
 }
+
 /* ASUS Xonar U1 / U3 controls */
 
 static int snd_xonar_u1_switch_get(struct snd_kcontrol *kcontrol,
 				   struct snd_ctl_elem_value *ucontrol)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
-
-	ucontrol->value.integer.value[0] = !!(mixer->xonar_u1_status & 0x02);
+	ucontrol->value.integer.value[0] = !!(kcontrol->private_value & 0x02);
 	return 0;
 }
 
+static int snd_xonar_u1_switch_update(struct usb_mixer_interface *mixer,
+				      unsigned char status)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown)
+		err = -ENODEV;
+	else
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x08,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      50, 0, &status, 1);
+	up_read(&chip->shutdown_rwsem);
+	return err;
+}
+
 static int snd_xonar_u1_switch_put(struct snd_kcontrol *kcontrol,
 				   struct snd_ctl_elem_value *ucontrol)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
 	u8 old_status, new_status;
-	int err, changed;
+	int err;
 
-	old_status = mixer->xonar_u1_status;
+	old_status = kcontrol->private_value;
 	if (ucontrol->value.integer.value[0])
 		new_status = old_status | 0x02;
 	else
 		new_status = old_status & ~0x02;
-	changed = new_status != old_status;
-	down_read(&mixer->chip->shutdown_rwsem);
-	if (mixer->chip->shutdown)
-		err = -ENODEV;
-	else
-		err = snd_usb_ctl_msg(mixer->chip->dev,
-			      usb_sndctrlpipe(mixer->chip->dev, 0), 0x08,
-			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
-			      50, 0, &new_status, 1);
-	up_read(&mixer->chip->shutdown_rwsem);
-	if (err < 0)
-		return err;
-	mixer->xonar_u1_status = new_status;
-	return changed;
+	if (new_status == old_status)
+		return 0;
+
+	kcontrol->private_value = new_status;
+	err = snd_xonar_u1_switch_update(list->mixer, new_status);
+	return err < 0 ? err : 1;
+}
+
+static int snd_xonar_u1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_xonar_u1_switch_update(list->mixer,
+					  list->kctl->private_value);
 }
 
 static struct snd_kcontrol_new snd_xonar_u1_output_switch = {
@@ -561,82 +597,213 @@ static struct snd_kcontrol_new snd_xonar_u1_output_switch = {
 	.info = snd_ctl_boolean_mono_info,
 	.get = snd_xonar_u1_switch_get,
 	.put = snd_xonar_u1_switch_put,
+	.private_value = 0x05,
 };
 
 static int snd_xonar_u1_controls_create(struct usb_mixer_interface *mixer)
 {
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_xonar_u1_switch_resume,
+					  &snd_xonar_u1_output_switch, NULL);
+}
+
+/* Digidesign Mbox 1 clock source switch (internal/spdif) */
+
+static int snd_mbox1_switch_get(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kctl->private_value;
+	return 0;
+}
+
+static int snd_mbox1_switch_update(struct usb_mixer_interface *mixer, int val)
+{
+	struct snd_usb_audio *chip = mixer->chip;
 	int err;
+	unsigned char buff[3];
+
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown) {
+		err = -ENODEV;
+		goto err;
+	}
 
-	err = snd_ctl_add(mixer->chip->card,
-			  snd_ctl_new1(&snd_xonar_u1_output_switch, mixer));
+	/* Prepare for magic command to toggle clock source */
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_INTERFACE, 0x00, 0x500, buff, 1);
 	if (err < 0)
-		return err;
-	mixer->xonar_u1_status = 0x05;
-	return 0;
+		goto err;
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		goto err;
+
+	/* 2 possibilities:	Internal    -> send sample rate
+	 *			S/PDIF sync -> send zeroes
+	 * NB: Sample rate locked to 48kHz on purpose to
+	 *     prevent user from resetting the sample rate
+	 *     while S/PDIF sync is enabled and confusing
+	 *     this configuration.
+	 */
+	if (val == 0) {
+		buff[0] = 0x80;
+		buff[1] = 0xbb;
+		buff[2] = 0x00;
+	} else {
+		buff[0] = buff[1] = buff[2] = 0x00;
+	}
+
+	/* Send the magic command to toggle the clock source */
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_sndctrlpipe(chip->dev, 0), 0x1,
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		goto err;
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		goto err;
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x2, buff, 3);
+	if (err < 0)
+		goto err;
+
+err:
+	up_read(&chip->shutdown_rwsem);
+	return err;
+}
+
+static int snd_mbox1_switch_put(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int err;
+	bool cur_val, new_val;
+
+	cur_val = kctl->private_value;
+	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
+
+	kctl->private_value = new_val;
+	err = snd_mbox1_switch_update(mixer, new_val);
+	return err < 0 ? err : 1;
+}
+
+static int snd_mbox1_switch_info(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Internal",
+		"S/PDIF"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_mbox1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_mbox1_switch_update(list->mixer, list->kctl->private_value);
+}
+
+static struct snd_kcontrol_new snd_mbox1_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Clock Source",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_mbox1_switch_info,
+	.get = snd_mbox1_switch_get,
+	.put = snd_mbox1_switch_put,
+	.private_value = 0
+};
+
+static int snd_mbox1_create_sync_switch(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_mbox1_switch_resume,
+					  &snd_mbox1_switch, NULL);
 }
 
 /* Native Instruments device quirks */
 
 #define _MAKE_NI_CONTROL(bRequest,wIndex) ((bRequest) << 16 | (wIndex))
 
-static int snd_nativeinstruments_control_get(struct snd_kcontrol *kcontrol,
-					     struct snd_ctl_elem_value *ucontrol)
+static int snd_ni_control_init_val(struct usb_mixer_interface *mixer,
+				   struct snd_kcontrol *kctl)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
 	struct usb_device *dev = mixer->chip->dev;
-	u8 bRequest = (kcontrol->private_value >> 16) & 0xff;
-	u16 wIndex = kcontrol->private_value & 0xffff;
-	u8 tmp;
-	int ret;
-
-	down_read(&mixer->chip->shutdown_rwsem);
-	if (mixer->chip->shutdown)
-		ret = -ENODEV;
-	else
-		ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), bRequest,
-				  USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
-				  0, wIndex,
-				  &tmp, sizeof(tmp));
-	up_read(&mixer->chip->shutdown_rwsem);
+	unsigned int pval = kctl->private_value;
+	u8 value;
+	int err;
 
-	if (ret < 0) {
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      (pval >> 16) & 0xff,
+			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			      0, pval & 0xffff, &value, 1);
+	if (err < 0) {
 		dev_err(&dev->dev,
-			"unable to issue vendor read request (ret = %d)", ret);
-		return ret;
+			"unable to issue vendor read request (ret = %d)", err);
+		return err;
 	}
 
-	ucontrol->value.integer.value[0] = tmp;
+	kctl->private_value |= (value << 24);
+	return 0;
+}
 
+static int snd_nativeinstruments_control_get(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value >> 24;
 	return 0;
 }
 
+static int snd_ni_update_cur_val(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	int err;
+
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown)
+		err = -ENODEV;
+	else
+		err = usb_control_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+				      (pval >> 16) & 0xff,
+				      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+				      pval >> 24, pval & 0xffff, NULL, 0, 1000);
+	up_read(&chip->shutdown_rwsem);
+	return err;
+}
+
 static int snd_nativeinstruments_control_put(struct snd_kcontrol *kcontrol,
 					     struct snd_ctl_elem_value *ucontrol)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
-	struct usb_device *dev = mixer->chip->dev;
-	u8 bRequest = (kcontrol->private_value >> 16) & 0xff;
-	u16 wIndex = kcontrol->private_value & 0xffff;
-	u16 wValue = ucontrol->value.integer.value[0];
-	int ret;
-
-	down_read(&mixer->chip->shutdown_rwsem);
-	if (mixer->chip->shutdown)
-		ret = -ENODEV;
-	else
-		ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), bRequest,
-				  USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
-				  wValue, wIndex,
-				  NULL, 0, 1000);
-	up_read(&mixer->chip->shutdown_rwsem);
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 oldval = (kcontrol->private_value >> 24) & 0xff;
+	u8 newval = ucontrol->value.integer.value[0];
+	int err;
 
-	if (ret < 0) {
-		dev_err(&dev->dev,
-			"unable to issue vendor write request (ret = %d)", ret);
-		return ret;
-	}
+	if (oldval == newval)
+		return 0;
 
-	return 0;
+	kcontrol->private_value &= ~(0xff << 24);
+	kcontrol->private_value |= newval;
+	err = snd_ni_update_cur_val(list);
+	return err < 0 ? err : 1;
 }
 
 static struct snd_kcontrol_new snd_nativeinstruments_ta6_mixers[] = {
@@ -707,16 +874,17 @@ static int snd_nativeinstruments_create_mixer(struct usb_mixer_interface *mixer,
 	};
 
 	for (i = 0; i < count; i++) {
-		struct snd_kcontrol *c;
+		struct usb_mixer_elem_list *list;
 
 		template.name = kc[i].name;
 		template.private_value = kc[i].private_value;
 
-		c = snd_ctl_new1(&template, mixer);
-		err = snd_ctl_add(mixer->chip->card, c);
-
+		err = add_single_ctl_with_resume(mixer, 0,
+						 snd_ni_update_cur_val,
+						 &template, &list);
 		if (err < 0)
 			break;
+		snd_ni_control_init_val(mixer, list->kctl);
 	}
 
 	return err;
@@ -724,170 +892,88 @@ static int snd_nativeinstruments_create_mixer(struct usb_mixer_interface *mixer,
 
 /* M-Audio FastTrack Ultra quirks */
 /* FTU Effect switch (also used by C400/C600) */
-struct snd_ftu_eff_switch_priv_val {
-	struct usb_mixer_interface *mixer;
-	int cached_value;
-	int is_cached;
-	int bUnitID;
-	int validx;
-};
-
 static int snd_ftu_eff_switch_info(struct snd_kcontrol *kcontrol,
 					struct snd_ctl_elem_info *uinfo)
 {
-	static const char *texts[8] = {"Room 1",
-				       "Room 2",
-				       "Room 3",
-				       "Hall 1",
-				       "Hall 2",
-				       "Plate",
-				       "Delay",
-				       "Echo"
+	static const char *const texts[8] = {
+		"Room 1", "Room 2", "Room 3", "Hall 1",
+		"Hall 2", "Plate", "Delay", "Echo"
 	};
 
-	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
-	uinfo->count = 1;
-	uinfo->value.enumerated.items = 8;
-	if (uinfo->value.enumerated.item > 7)
-		uinfo->value.enumerated.item = 7;
-	strcpy(uinfo->value.enumerated.name,
-		texts[uinfo->value.enumerated.item]);
-
-	return 0;
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
 }
 
-static int snd_ftu_eff_switch_get(struct snd_kcontrol *kctl,
-					struct snd_ctl_elem_value *ucontrol)
+static int snd_ftu_eff_switch_init(struct usb_mixer_interface *mixer,
+				   struct snd_kcontrol *kctl)
 {
-	struct snd_usb_audio *chip;
-	struct usb_mixer_interface *mixer;
-	struct snd_ftu_eff_switch_priv_val *pval;
+	struct usb_device *dev = mixer->chip->dev;
+	unsigned int pval = kctl->private_value;
 	int err;
 	unsigned char value[2];
-	int id, validx;
-
-	const int val_len = 2;
 
 	value[0] = 0x00;
 	value[1] = 0x00;
 
-	pval = (struct snd_ftu_eff_switch_priv_val *)
-		kctl->private_value;
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			      pval & 0xff00,
+			      snd_usb_ctrl_intf(mixer->chip) | ((pval & 0xff) << 8),
+			      value, 2);
+	if (err < 0)
+		return err;
 
-	if (pval->is_cached) {
-		ucontrol->value.enumerated.item[0] = pval->cached_value;
-		return 0;
-	}
+	kctl->private_value |= value[0] << 24;
+	return 0;
+}
 
-	mixer = (struct usb_mixer_interface *) pval->mixer;
-	if (snd_BUG_ON(!mixer))
-		return -EINVAL;
+static int snd_ftu_eff_switch_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kctl->private_value >> 24;
+	return 0;
+}
 
-	chip = (struct snd_usb_audio *) mixer->chip;
-	if (snd_BUG_ON(!chip))
-		return -EINVAL;
+static int snd_ftu_eff_switch_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	unsigned char value[2];
+	int err;
 
-	id = pval->bUnitID;
-	validx = pval->validx;
+	value[0] = pval >> 24;
+	value[1] = 0;
 
-	down_read(&mixer->chip->shutdown_rwsem);
-	if (mixer->chip->shutdown)
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown)
 		err = -ENODEV;
 	else
 		err = snd_usb_ctl_msg(chip->dev,
-			usb_rcvctrlpipe(chip->dev, 0), UAC_GET_CUR,
-			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
-			validx << 8, snd_usb_ctrl_intf(chip) | (id << 8),
-			value, val_len);
-	up_read(&mixer->chip->shutdown_rwsem);
-	if (err < 0)
-		return err;
-
-	ucontrol->value.enumerated.item[0] = value[0];
-	pval->cached_value = value[0];
-	pval->is_cached = 1;
-
-	return 0;
+				      usb_sndctrlpipe(chip->dev, 0),
+				      UAC_SET_CUR,
+				      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+				      pval & 0xff00,
+				      snd_usb_ctrl_intf(chip) | ((pval & 0xff) << 8),
+				      value, 2);
+	up_read(&chip->shutdown_rwsem);
+	return err;
 }
 
 static int snd_ftu_eff_switch_put(struct snd_kcontrol *kctl,
 					struct snd_ctl_elem_value *ucontrol)
 {
-	struct snd_usb_audio *chip;
-	struct snd_ftu_eff_switch_priv_val *pval;
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	unsigned int pval = list->kctl->private_value;
+	int cur_val, err, new_val;
 
-	struct usb_mixer_interface *mixer;
-	int changed, cur_val, err, new_val;
-	unsigned char value[2];
-	int id, validx;
-
-	const int val_len = 2;
-
-	changed = 0;
-
-	pval = (struct snd_ftu_eff_switch_priv_val *)
-		kctl->private_value;
-	cur_val = pval->cached_value;
+	cur_val = pval >> 24;
 	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
 
-	mixer = (struct usb_mixer_interface *) pval->mixer;
-	if (snd_BUG_ON(!mixer))
-		return -EINVAL;
-
-	chip = (struct snd_usb_audio *) mixer->chip;
-	if (snd_BUG_ON(!chip))
-		return -EINVAL;
-
-	id = pval->bUnitID;
-	validx = pval->validx;
-
-	if (!pval->is_cached) {
-		/* Read current value */
-		down_read(&mixer->chip->shutdown_rwsem);
-		if (mixer->chip->shutdown)
-			err = -ENODEV;
-		else
-			err = snd_usb_ctl_msg(chip->dev,
-				usb_rcvctrlpipe(chip->dev, 0), UAC_GET_CUR,
-				USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
-				validx << 8, snd_usb_ctrl_intf(chip) | (id << 8),
-				value, val_len);
-		up_read(&mixer->chip->shutdown_rwsem);
-		if (err < 0)
-			return err;
-
-		cur_val = value[0];
-		pval->cached_value = cur_val;
-		pval->is_cached = 1;
-	}
-	/* update value if needed */
-	if (cur_val != new_val) {
-		value[0] = new_val;
-		value[1] = 0;
-		down_read(&mixer->chip->shutdown_rwsem);
-		if (mixer->chip->shutdown)
-			err = -ENODEV;
-		else
-			err = snd_usb_ctl_msg(chip->dev,
-				usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
-				USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
-				validx << 8, snd_usb_ctrl_intf(chip) | (id << 8),
-				value, val_len);
-		up_read(&mixer->chip->shutdown_rwsem);
-		if (err < 0)
-			return err;
-
-		pval->cached_value = new_val;
-		pval->is_cached = 1;
-		changed = 1;
-	}
-
-	return changed;
-}
-
-static void kctl_private_value_free(struct snd_kcontrol *kctl)
-{
-	kfree((void *)kctl->private_value);
+	kctl->private_value &= ~(0xff << 24);
+	kctl->private_value |= new_val << 24;
+	err = snd_ftu_eff_switch_update(list);
+	return err < 0 ? err : 1;
 }
 
 static int snd_ftu_create_effect_switch(struct usb_mixer_interface *mixer,
@@ -902,33 +988,16 @@ static int snd_ftu_create_effect_switch(struct usb_mixer_interface *mixer,
 		.get = snd_ftu_eff_switch_get,
 		.put = snd_ftu_eff_switch_put
 	};
-
+	struct usb_mixer_elem_list *list;
 	int err;
-	struct snd_kcontrol *kctl;
-	struct snd_ftu_eff_switch_priv_val *pval;
-
-	pval = kzalloc(sizeof(*pval), GFP_KERNEL);
-	if (!pval)
-		return -ENOMEM;
-
-	pval->cached_value = 0;
-	pval->is_cached = 0;
-	pval->mixer = mixer;
-	pval->bUnitID = bUnitID;
-	pval->validx = validx;
-
-	template.private_value = (unsigned long) pval;
-	kctl = snd_ctl_new1(&template, mixer->chip);
-	if (!kctl) {
-		kfree(pval);
-		return -ENOMEM;
-	}
 
-	kctl->private_free = kctl_private_value_free;
-	err = snd_ctl_add(mixer->chip->card, kctl);
+	err = add_single_ctl_with_resume(mixer, bUnitID,
+					 snd_ftu_eff_switch_update,
+					 &template, &list);
 	if (err < 0)
 		return err;
-
+	list->kctl->private_value = (validx << 8) | bUnitID;
+	snd_ftu_eff_switch_init(mixer, list->kctl);
 	return 0;
 }
 
@@ -1110,7 +1179,7 @@ void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
 	int unitid = 12; /* SamleRate ExtensionUnit ID */
 
 	list_for_each_entry(mixer, &chip->mixer_list, list) {
-		cval = mixer->id_elems[unitid];
+		cval = (struct usb_mixer_elem_info *)mixer->id_elems[unitid];
 		if (cval) {
 			snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR,
 						    cval->control << 8,
@@ -1440,7 +1509,8 @@ static int snd_microii_spdif_info(struct snd_kcontrol *kcontrol,
 static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
 	int err;
 	struct usb_interface *iface;
 	struct usb_host_interface *alts;
@@ -1448,17 +1518,23 @@ static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
 	unsigned char data[3];
 	int rate;
 
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown) {
+		err = -ENODEV;
+		goto end;
+	}
+
 	ucontrol->value.iec958.status[0] = kcontrol->private_value & 0xff;
 	ucontrol->value.iec958.status[1] = (kcontrol->private_value >> 8) & 0xff;
 	ucontrol->value.iec958.status[2] = 0x00;
 
 	/* use known values for that card: interface#1 altsetting#1 */
-	iface = usb_ifnum_to_if(mixer->chip->dev, 1);
+	iface = usb_ifnum_to_if(chip->dev, 1);
 	alts = &iface->altsetting[1];
 	ep = get_endpoint(alts, 0)->bEndpointAddress;
 
-	err = snd_usb_ctl_msg(mixer->chip->dev,
-			usb_rcvctrlpipe(mixer->chip->dev, 0),
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_rcvctrlpipe(chip->dev, 0),
 			UAC_GET_CUR,
 			USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
 			UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
@@ -1473,22 +1549,27 @@ static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
 			IEC958_AES3_CON_FS_48000 : IEC958_AES3_CON_FS_44100;
 
 	err = 0;
-end:
+ end:
+	up_read(&chip->shutdown_rwsem);
 	return err;
 }
 
-static int snd_microii_spdif_default_put(struct snd_kcontrol *kcontrol,
-	struct snd_ctl_elem_value *ucontrol)
+static int snd_microii_spdif_default_update(struct usb_mixer_elem_list *list)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
-	int err;
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
 	u8 reg;
-	unsigned long priv_backup = kcontrol->private_value;
+	int err;
 
-	reg = ((ucontrol->value.iec958.status[1] & 0x0f) << 4) |
-			(ucontrol->value.iec958.status[0] & 0x0f);
-	err = snd_usb_ctl_msg(mixer->chip->dev,
-			usb_sndctrlpipe(mixer->chip->dev, 0),
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown) {
+		err = -ENODEV;
+		goto end;
+	}
+
+	reg = ((pval >> 4) & 0xf0) | (pval & 0x0f);
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0),
 			UAC_SET_CUR,
 			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			reg,
@@ -1498,15 +1579,10 @@ static int snd_microii_spdif_default_put(struct snd_kcontrol *kcontrol,
 	if (err < 0)
 		goto end;
 
-	kcontrol->private_value &= 0xfffff0f0;
-	kcontrol->private_value |= (ucontrol->value.iec958.status[1] & 0x0f) << 8;
-	kcontrol->private_value |= (ucontrol->value.iec958.status[0] & 0x0f);
-
-	reg = (ucontrol->value.iec958.status[0] & IEC958_AES0_NONAUDIO) ?
-			0xa0 : 0x20;
-	reg |= (ucontrol->value.iec958.status[1] >> 4) & 0x0f;
-	err = snd_usb_ctl_msg(mixer->chip->dev,
-			usb_sndctrlpipe(mixer->chip->dev, 0),
+	reg = (pval & IEC958_AES0_NONAUDIO) ? 0xa0 : 0x20;
+	reg |= (pval >> 12) & 0x0f;
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0),
 			UAC_SET_CUR,
 			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			reg,
@@ -1516,16 +1592,36 @@ static int snd_microii_spdif_default_put(struct snd_kcontrol *kcontrol,
 	if (err < 0)
 		goto end;
 
-	kcontrol->private_value &= 0xffff0fff;
-	kcontrol->private_value |= (ucontrol->value.iec958.status[1] & 0xf0) << 8;
+ end:
+	up_read(&chip->shutdown_rwsem);
+	return err;
+}
+
+static int snd_microii_spdif_default_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	unsigned int pval, pval_old;
+	int err;
+
+	pval = pval_old = kcontrol->private_value;
+	pval &= 0xfffff0f0;
+	pval |= (ucontrol->value.iec958.status[1] & 0x0f) << 8;
+	pval |= (ucontrol->value.iec958.status[0] & 0x0f);
+
+	pval &= 0xffff0fff;
+	pval |= (ucontrol->value.iec958.status[1] & 0xf0) << 8;
 
 	/* The frequency bits in AES3 cannot be set via register access. */
 
 	/* Silently ignore any bits from the request that cannot be set. */
 
-	err = (priv_backup != kcontrol->private_value);
-end:
-	return err;
+	if (pval == pval_old)
+		return 0;
+
+	kcontrol->private_value = pval;
+	err = snd_microii_spdif_default_update(list);
+	return err < 0 ? err : 1;
 }
 
 static int snd_microii_spdif_mask_get(struct snd_kcontrol *kcontrol,
@@ -1547,15 +1643,20 @@ static int snd_microii_spdif_switch_get(struct snd_kcontrol *kcontrol,
 	return 0;
 }
 
-static int snd_microii_spdif_switch_put(struct snd_kcontrol *kcontrol,
-	struct snd_ctl_elem_value *ucontrol)
+static int snd_microii_spdif_switch_update(struct usb_mixer_elem_list *list)
 {
-	struct usb_mixer_interface *mixer = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	u8 reg = list->kctl->private_value;
 	int err;
-	u8 reg = ucontrol->value.integer.value[0] ? 0x28 : 0x2a;
 
-	err = snd_usb_ctl_msg(mixer->chip->dev,
-			usb_sndctrlpipe(mixer->chip->dev, 0),
+	down_read(&chip->shutdown_rwsem);
+	if (chip->shutdown) {
+		err = -ENODEV;
+		goto end;
+	}
+
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0),
 			UAC_SET_CUR,
 			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
 			reg,
@@ -1563,15 +1664,27 @@ static int snd_microii_spdif_switch_put(struct snd_kcontrol *kcontrol,
 			NULL,
 			0);
 
-	if (!err) {
-		err = (reg != (kcontrol->private_value & 0x0ff));
-		if (err)
-			kcontrol->private_value = reg;
-	}
-
+ end:
+	up_read(&chip->shutdown_rwsem);
 	return err;
 }
 
+static int snd_microii_spdif_switch_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 reg;
+	int err;
+
+	reg = ucontrol->value.integer.value[0] ? 0x28 : 0x2a;
+	if (reg != list->kctl->private_value)
+		return 0;
+
+	kcontrol->private_value = reg;
+	err = snd_microii_spdif_switch_update(list);
+	return err < 0 ? err : 1;
+}
+
 static struct snd_kcontrol_new snd_microii_mixer_spdif[] = {
 	{
 		.iface =    SNDRV_CTL_ELEM_IFACE_PCM,
@@ -1601,10 +1714,17 @@ static struct snd_kcontrol_new snd_microii_mixer_spdif[] = {
 static int snd_microii_controls_create(struct usb_mixer_interface *mixer)
 {
 	int err, i;
+	static usb_mixer_elem_resume_func_t resume_funcs[] = {
+		snd_microii_spdif_default_update,
+		NULL,
+		snd_microii_spdif_switch_update
+	};
 
 	for (i = 0; i < ARRAY_SIZE(snd_microii_mixer_spdif); ++i) {
-		err = snd_ctl_add(mixer->chip->card,
-			snd_ctl_new1(&snd_microii_mixer_spdif[i], mixer));
+		err = add_single_ctl_with_resume(mixer, 0,
+						 resume_funcs[i],
+						 &snd_microii_mixer_spdif[i],
+						 NULL);
 		if (err < 0)
 			return err;
 	}
@@ -1661,6 +1781,10 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 		err = snd_microii_controls_create(mixer);
 		break;
 
+	case USB_ID(0x0dba, 0x1000): /* Digidesign Mbox 1 */
+		err = snd_mbox1_create_sync_switch(mixer);
+		break;
+
 	case USB_ID(0x17cc, 0x1011): /* Traktor Audio 6 */
 		err = snd_nativeinstruments_create_mixer(mixer,
 				snd_nativeinstruments_ta6_mixers,
@@ -1677,6 +1801,14 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 		/* detection is disabled in mixer_maps.c */
 		err = snd_create_std_mono_table(mixer, ebox44_table);
 		break;
+
+	case USB_ID(0x1235, 0x8012): /* Focusrite Scarlett 6i6 */
+	case USB_ID(0x1235, 0x8002): /* Focusrite Scarlett 8i6 */
+	case USB_ID(0x1235, 0x8004): /* Focusrite Scarlett 18i6 */
+	case USB_ID(0x1235, 0x8014): /* Focusrite Scarlett 18i8 */
+	case USB_ID(0x1235, 0x800c): /* Focusrite Scarlett 18i20 */
+		err = snd_scarlett_controls_create(mixer);
+		break;
 	}
 
 	return err;
diff --git a/sound/usb/mixer_scarlett.c b/sound/usb/mixer_scarlett.c
new file mode 100644
index 000000000000..9109652b88b9
--- /dev/null
+++ b/sound/usb/mixer_scarlett.c
@@ -0,0 +1,1004 @@
+/*
+ *   Scarlett Driver for ALSA
+ *
+ *   Copyright (c) 2013 by Tobias Hoffmann
+ *   Copyright (c) 2013 by Robin Gareus <robin at gareus.org>
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai at suse.de>
+ *   Copyright (c) 2014 by Chris J Arges <chris.j.arges at canonical.com>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan at lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer at ife.ee.ethz.ch)
+ *
+ *   Code cleanup:
+ *   David Henningsson <david.henningsson at canonical.com>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ */
+
+/*
+ * Rewritten and extended to support more models, e.g. Scarlett 18i8.
+ *
+ * Auto-detection via UAC2 is not feasible to properly discover the vast
+ * majority of features. It's related to both Linux/ALSA's UAC2 as well as
+ * Focusrite's implementation of it. Eventually quirks may be sufficient but
+ * right now it's a major headache to work arount these things.
+ *
+ * NB. Neither the OSX nor the win driver provided by Focusrite performs
+ * discovery, they seem to operate the same as this driver.
+ */
+
+/* Mixer Interface for the Focusrite Scarlett 18i6 audio interface.
+ *
+ * The protocol was reverse engineered by looking at communication between
+ * Scarlett MixControl (v 1.2.128.0) and the Focusrite(R) Scarlett 18i6
+ * (firmware v305) using wireshark and usbmon in January 2013.
+ * Extended in July 2013.
+ *
+ * this mixer gives complete access to all features of the device:
+ *  - change Impedance of inputs (Line-in, Mic / Instrument, Hi-Z)
+ *  - select clock source
+ *  - dynamic input to mixer-matrix assignment
+ *  - 18 x 6 mixer-matrix gain stages
+ *  - bus routing & volume control
+ *  - automatic re-initialization on connect if device was power-cycled
+ *
+ * USB URB commands overview (bRequest = 0x01 = UAC2_CS_CUR)
+ * wIndex
+ * 0x01 Analog Input line/instrument impedance switch, wValue=0x0901 +
+ *      channel, data=Line/Inst (2bytes)
+ *      pad (-10dB) switch, wValue=0x0b01 + channel, data=Off/On (2bytes)
+ *      ?? wValue=0x0803/04, ?? (2bytes)
+ * 0x0a Master Volume, wValue=0x0200+bus[0:all + only 1..4?] data(2bytes)
+ *      Bus Mute/Unmute wValue=0x0100+bus[0:all + only 1..4?], data(2bytes)
+ * 0x28 Clock source, wValue=0x0100, data={1:int,2:spdif,3:adat} (1byte)
+ * 0x29 Set Sample-rate, wValue=0x0100, data=sample-rate(4bytes)
+ * 0x32 Mixer mux, wValue=0x0600 + mixer-channel, data=input-to-connect(2bytes)
+ * 0x33 Output mux, wValue=bus, data=input-to-connect(2bytes)
+ * 0x34 Capture mux, wValue=0...18, data=input-to-connect(2bytes)
+ * 0x3c Matrix Mixer gains, wValue=mixer-node  data=gain(2bytes)
+ *      ?? [sometimes](4bytes, e.g 0x000003be 0x000003bf ...03ff)
+ *
+ * USB reads: (i.e. actually issued by original software)
+ * 0x01 wValue=0x0901+channel (1byte!!), wValue=0x0b01+channed (1byte!!)
+ * 0x29 wValue=0x0100 sample-rate(4bytes)
+ *      wValue=0x0200 ?? 1byte (only once)
+ * 0x2a wValue=0x0100 ?? 4bytes, sample-rate2 ??
+ *
+ * USB reads with bRequest = 0x03 = UAC2_CS_MEM
+ * 0x3c wValue=0x0002 1byte: sync status (locked=1)
+ *      wValue=0x0000 18*2byte: peak meter (inputs)
+ *      wValue=0x0001 8(?)*2byte: peak meter (mix)
+ *      wValue=0x0003 6*2byte: peak meter (pcm/daw)
+ *
+ * USB write with bRequest = 0x03
+ * 0x3c Save settings to hardware: wValue=0x005a, data=0xa5
+ *
+ *
+ * <ditaa>
+ *  /--------------\    18chn            6chn    /--------------\
+ *  | Hardware  in +--+-------\        /------+--+ ALSA PCM out |
+ *  \--------------/  |       |        |      |  \--------------/
+ *                    |       |        |      |
+ *                    |       v        v      |
+ *                    |   +---------------+   |
+ *                    |    \ Matrix  Mux /    |
+ *                    |     +-----+-----+     |
+ *                    |           |           |
+ *                    |           | 18chn     |
+ *                    |           v           |
+ *                    |     +-----------+     |
+ *                    |     | Mixer     |     |
+ *                    |     |    Matrix |     |
+ *                    |     |           |     |
+ *                    |     | 18x6 Gain |     |
+ *                    |     |   stages  |     |
+ *                    |     +-----+-----+     |
+ *                    |           |           |
+ *                    |           |           |
+ *                    | 18chn     | 6chn      | 6chn
+ *                    v           v           v
+ *                    =========================
+ *             +---------------+     +--—------------+
+ *              \ Output  Mux /       \ Capture Mux /
+ *               +-----+-----+         +-----+-----+
+ *                     |                     |
+ *                     | 6chn                |
+ *                     v                     |
+ *              +-------------+              |
+ *              | Master Gain |              |
+ *              +------+------+              |
+ *                     |                     |
+ *                     | 6chn                | 18chn
+ *                     | (3 stereo pairs)    |
+ *  /--------------\   |                     |   /--------------\
+ *  | Hardware out |<--/                     \-->| ALSA PCM  in |
+ *  \--------------/                             \--------------/
+ * </ditaa>
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio-v2.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "helper.h"
+#include "power.h"
+
+#include "mixer_scarlett.h"
+
+/* some gui mixers can't handle negative ctl values */
+#define SND_SCARLETT_LEVEL_BIAS 128
+#define SND_SCARLETT_MATRIX_IN_MAX 18
+#define SND_SCARLETT_CONTROLS_MAX 10
+#define SND_SCARLETT_OFFSETS_MAX 5
+
+enum {
+	SCARLETT_OUTPUTS,
+	SCARLETT_SWITCH_IMPEDANCE,
+	SCARLETT_SWITCH_PAD,
+};
+
+enum {
+	SCARLETT_OFFSET_PCM = 0,
+	SCARLETT_OFFSET_ANALOG = 1,
+	SCARLETT_OFFSET_SPDIF = 2,
+	SCARLETT_OFFSET_ADAT = 3,
+	SCARLETT_OFFSET_MIX = 4,
+};
+
+struct scarlett_mixer_elem_enum_info {
+	int start;
+	int len;
+	int offsets[SND_SCARLETT_OFFSETS_MAX];
+	char const * const *names;
+};
+
+struct scarlett_mixer_control {
+	unsigned char num;
+	unsigned char type;
+	const char *name;
+};
+
+struct scarlett_device_info {
+	int matrix_in;
+	int matrix_out;
+	int input_len;
+	int output_len;
+
+	struct scarlett_mixer_elem_enum_info opt_master;
+	struct scarlett_mixer_elem_enum_info opt_matrix;
+
+	/* initial values for matrix mux */
+	int matrix_mux_init[SND_SCARLETT_MATRIX_IN_MAX];
+
+	int num_controls;	/* number of items in controls */
+	const struct scarlett_mixer_control controls[SND_SCARLETT_CONTROLS_MAX];
+};
+
+/********************** Enum Strings *************************/
+
+static const struct scarlett_mixer_elem_enum_info opt_pad = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"0dB", "-10dB"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_impedance = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"Line", "Hi-Z"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_clock = {
+	.start = 1,
+	.len = 3,
+	.offsets = {},
+	.names = (char const * const []){
+		"Internal", "SPDIF", "ADAT"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_sync = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"No Lock", "Locked"
+	}
+};
+
+static int scarlett_ctl_switch_info(struct snd_kcontrol *kctl,
+		struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 1;
+	return 0;
+}
+
+static int scarlett_ctl_switch_get(struct snd_kcontrol *kctl,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, err, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &val);
+		if (err < 0)
+			return err;
+
+		val = !val; /* invert mute logic for mixer */
+		ucontrol->value.integer.value[i] = val;
+	}
+
+	return 0;
+}
+
+static int scarlett_ctl_switch_put(struct snd_kcontrol *kctl,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, changed = 0;
+	int err, oval, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &oval);
+		if (err < 0)
+			return err;
+
+		val = ucontrol->value.integer.value[i];
+		val = !val;
+		if (oval != val) {
+			err = snd_usb_set_cur_mix_value(elem, i, i, val);
+			if (err < 0)
+				return err;
+
+			changed = 1;
+		}
+	}
+
+	return changed;
+}
+
+static int scarlett_ctl_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem =
+		container_of(list, struct usb_mixer_elem_info, head);
+	int i;
+
+	for (i = 0; i < elem->channels; i++)
+		if (elem->cached & (1 << i))
+			snd_usb_set_cur_mix_value(elem, i, i,
+						  elem->cache_val[i]);
+	return 0;
+}
+
+static int scarlett_ctl_info(struct snd_kcontrol *kctl,
+			     struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = (int)kctl->private_value +
+		SND_SCARLETT_LEVEL_BIAS;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int scarlett_ctl_get(struct snd_kcontrol *kctl,
+			    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, err, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &val);
+		if (err < 0)
+			return err;
+
+		val = clamp(val / 256, -128, (int)kctl->private_value) +
+				    SND_SCARLETT_LEVEL_BIAS;
+		ucontrol->value.integer.value[i] = val;
+	}
+
+	return 0;
+}
+
+static int scarlett_ctl_put(struct snd_kcontrol *kctl,
+			    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, changed = 0;
+	int err, oval, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &oval);
+		if (err < 0)
+			return err;
+
+		val = ucontrol->value.integer.value[i] -
+			SND_SCARLETT_LEVEL_BIAS;
+		val = val * 256;
+		if (oval != val) {
+			err = snd_usb_set_cur_mix_value(elem, i, i, val);
+			if (err < 0)
+				return err;
+
+			changed = 1;
+		}
+	}
+
+	return changed;
+}
+
+static void scarlett_generate_name(int i, char *dst, int offsets[])
+{
+	if (i > offsets[SCARLETT_OFFSET_MIX])
+		sprintf(dst, "Mix %c",
+			'A'+(i - offsets[SCARLETT_OFFSET_MIX] - 1));
+	else if (i > offsets[SCARLETT_OFFSET_ADAT])
+		sprintf(dst, "ADAT %d", i - offsets[SCARLETT_OFFSET_ADAT]);
+	else if (i > offsets[SCARLETT_OFFSET_SPDIF])
+		sprintf(dst, "SPDIF %d", i - offsets[SCARLETT_OFFSET_SPDIF]);
+	else if (i > offsets[SCARLETT_OFFSET_ANALOG])
+		sprintf(dst, "Analog %d", i - offsets[SCARLETT_OFFSET_ANALOG]);
+	else if (i > offsets[SCARLETT_OFFSET_PCM])
+		sprintf(dst, "PCM %d", i - offsets[SCARLETT_OFFSET_PCM]);
+	else
+		sprintf(dst, "Off");
+}
+
+static int scarlett_ctl_enum_dynamic_info(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	unsigned int items = opt->len;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+	uinfo->count = elem->channels;
+	uinfo->value.enumerated.items = items;
+
+	if (uinfo->value.enumerated.item >= items)
+		uinfo->value.enumerated.item = items - 1;
+
+	/* generate name dynamically based on item number and offset info */
+	scarlett_generate_name(uinfo->value.enumerated.item,
+			       uinfo->value.enumerated.name,
+			       opt->offsets);
+
+	return 0;
+}
+
+static int scarlett_ctl_enum_info(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+
+	return snd_ctl_enum_info(uinfo, elem->channels, opt->len,
+				 (const char * const *)opt->names);
+}
+
+static int scarlett_ctl_enum_get(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	int err, val;
+
+	err = snd_usb_get_cur_mix_value(elem, 0, 0, &val);
+	if (err < 0)
+		return err;
+
+	val = clamp(val - opt->start, 0, opt->len-1);
+
+	ucontrol->value.enumerated.item[0] = val;
+
+	return 0;
+}
+
+static int scarlett_ctl_enum_put(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	int err, oval, val;
+
+	err = snd_usb_get_cur_mix_value(elem, 0, 0, &oval);
+	if (err < 0)
+		return err;
+
+	val = ucontrol->value.integer.value[0];
+	val = val + opt->start;
+	if (val != oval) {
+		snd_usb_set_cur_mix_value(elem, 0, 0, val);
+		return 1;
+	}
+	return 0;
+}
+
+static int scarlett_ctl_enum_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem =
+		container_of(list, struct usb_mixer_elem_info, head);
+
+	if (elem->cached)
+		snd_usb_set_cur_mix_value(elem, 0, 0, *elem->cache_val);
+	return 0;
+}
+
+static int scarlett_ctl_meter_get(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	unsigned char buf[2 * MAX_CHANNELS] = {0, };
+	int wValue = (elem->control << 8) | elem->idx_off;
+	int idx = snd_usb_ctrl_intf(chip) | (elem->head.id << 8);
+	int err;
+
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0),
+				UAC2_CS_MEM,
+				USB_RECIP_INTERFACE | USB_TYPE_CLASS |
+				USB_DIR_IN, wValue, idx, buf, elem->channels);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.enumerated.item[0] = clamp((int)buf[0], 0, 1);
+	return 0;
+}
+
+static struct snd_kcontrol_new usb_scarlett_ctl_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_switch_info,
+	.get =  scarlett_ctl_switch_get,
+	.put =  scarlett_ctl_switch_put,
+};
+
+static const DECLARE_TLV_DB_SCALE(db_scale_scarlett_gain, -12800, 100, 0);
+
+static struct snd_kcontrol_new usb_scarlett_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett_ctl_info,
+	.get =  scarlett_ctl_get,
+	.put =  scarlett_ctl_put,
+	.private_value = 6,  /* max value */
+	.tlv = { .p = db_scale_scarlett_gain }
+};
+
+static struct snd_kcontrol_new usb_scarlett_ctl_master = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett_ctl_info,
+	.get =  scarlett_ctl_get,
+	.put =  scarlett_ctl_put,
+	.private_value = 6,  /* max value */
+	.tlv = { .p = db_scale_scarlett_gain }
+};
+
+static struct snd_kcontrol_new usb_scarlett_ctl_enum = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_enum_info,
+	.get =  scarlett_ctl_enum_get,
+	.put =  scarlett_ctl_enum_put,
+};
+
+static struct snd_kcontrol_new usb_scarlett_ctl_dynamic_enum = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_enum_dynamic_info,
+	.get =  scarlett_ctl_enum_get,
+	.put =  scarlett_ctl_enum_put,
+};
+
+static struct snd_kcontrol_new usb_scarlett_ctl_sync = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+	.name = "",
+	.info = scarlett_ctl_enum_info,
+	.get =  scarlett_ctl_meter_get,
+};
+
+static int add_new_ctl(struct usb_mixer_interface *mixer,
+		       const struct snd_kcontrol_new *ncontrol,
+		       usb_mixer_elem_resume_func_t resume,
+		       int index, int offset, int num,
+		       int val_type, int channels, const char *name,
+		       const struct scarlett_mixer_elem_enum_info *opt,
+		       struct usb_mixer_elem_info **elem_ret
+)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+	int err;
+
+	elem = kzalloc(sizeof(*elem), GFP_KERNEL);
+	if (!elem)
+		return -ENOMEM;
+
+	elem->head.mixer = mixer;
+	elem->head.resume = resume;
+	elem->control = offset;
+	elem->idx_off = num;
+	elem->head.id = index;
+	elem->val_type = val_type;
+
+	elem->channels = channels;
+
+	/* add scarlett_mixer_elem_enum_info struct */
+	elem->private_data = (void *)opt;
+
+	kctl = snd_ctl_new1(ncontrol, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	strlcpy(kctl->id.name, name, sizeof(kctl->id.name));
+
+	err = snd_usb_mixer_add_control(&elem->head, kctl);
+	if (err < 0)
+		return err;
+
+	if (elem_ret)
+		*elem_ret = elem;
+
+	return 0;
+}
+
+static int add_output_ctls(struct usb_mixer_interface *mixer,
+			   int index, const char *name,
+			   const struct scarlett_device_info *info)
+{
+	int err;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	struct usb_mixer_elem_info *elem;
+
+	/* Add mute switch */
+	snprintf(mx, sizeof(mx), "Master %d (%s) Playback Switch",
+		index + 1, name);
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_switch,
+			  scarlett_ctl_resume, 0x0a, 0x01,
+			  2*index+1, USB_MIXER_S16, 2, mx, NULL, &elem);
+	if (err < 0)
+		return err;
+
+	/* Add volume control and initialize to 0 */
+	snprintf(mx, sizeof(mx), "Master %d (%s) Playback Volume",
+		index + 1, name);
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_master,
+			  scarlett_ctl_resume, 0x0a, 0x02,
+			  2*index+1, USB_MIXER_S16, 2, mx, NULL, &elem);
+	if (err < 0)
+		return err;
+
+	/* Add L channel source playback enumeration */
+	snprintf(mx, sizeof(mx), "Master %dL (%s) Source Playback Enum",
+		index + 1, name);
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+			  scarlett_ctl_enum_resume, 0x33, 0x00,
+			  2*index, USB_MIXER_S16, 1, mx, &info->opt_master,
+			  &elem);
+	if (err < 0)
+		return err;
+
+	/* Add R channel source playback enumeration */
+	snprintf(mx, sizeof(mx), "Master %dR (%s) Source Playback Enum",
+		index + 1, name);
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+			  scarlett_ctl_enum_resume, 0x33, 0x00,
+			  2*index+1, USB_MIXER_S16, 1, mx, &info->opt_master,
+			  &elem);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/********************** device-specific config *************************/
+
+/*  untested...  */
+static struct scarlett_device_info s6i6_info = {
+	.matrix_in = 18,
+	.matrix_out = 8,
+	.input_len = 6,
+	.output_len = 6,
+
+	.opt_master = {
+		.start = -1,
+		.len = 27,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 19,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.num_controls = 0,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 1, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		12, 13, 14, 15,                 /* Analog -> 1..4 */
+		16, 17,                          /* SPDIF -> 5,6 */
+		0, 1, 2, 3, 4, 5, 6, 7,     /* PCM[1..12] -> 7..18 */
+		8, 9, 10, 11
+	}
+};
+
+/*  untested...  */
+static struct scarlett_device_info s8i6_info = {
+	.matrix_in = 18,
+	.matrix_out = 6,
+	.input_len = 8,
+	.output_len = 6,
+
+	.opt_master = {
+		.start = -1,
+		.len = 25,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 19,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.num_controls = 7,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		12, 13, 14, 15,                 /* Analog -> 1..4 */
+		16, 17,                          /* SPDIF -> 5,6 */
+		0, 1, 2, 3, 4, 5, 6, 7,     /* PCM[1..12] -> 7..18 */
+		8, 9, 10, 11
+	}
+};
+
+static struct scarlett_device_info s18i6_info = {
+	.matrix_in = 18,
+	.matrix_out = 6,
+	.input_len = 18,
+	.output_len = 6,
+
+	.opt_master = {
+		.start = -1,
+		.len = 31,
+		.offsets = {0, 6, 14, 16, 24},
+		.names = NULL,
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 25,
+		.offsets = {0, 6, 14, 16, 24},
+		.names = NULL,
+	},
+
+	.num_controls = 5,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		 6,  7,  8,  9, 10, 11, 12, 13, /* Analog -> 1..8 */
+		16, 17, 18, 19, 20, 21,     /* ADAT[1..6] -> 9..14 */
+		14, 15,                          /* SPDIF -> 15,16 */
+		0, 1                          /* PCM[1,2] -> 17,18 */
+	}
+};
+
+static struct scarlett_device_info s18i8_info = {
+	.matrix_in = 18,
+	.matrix_out = 8,
+	.input_len = 18,
+	.output_len = 8,
+
+	.opt_master = {
+		.start = -1,
+		.len = 35,
+		.offsets = {0, 8, 16, 18, 26},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 27,
+		.offsets = {0, 8, 16, 18, 26},
+		.names = NULL
+	},
+
+	.num_controls = 10,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone 1" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "Headphone 2" },
+		{ .num = 3, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 1, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		 8,  9, 10, 11, 12, 13, 14, 15, /* Analog -> 1..8 */
+		18, 19, 20, 21, 22, 23,     /* ADAT[1..6] -> 9..14 */
+		16, 17,                          /* SPDIF -> 15,16 */
+		0, 1                          /* PCM[1,2] -> 17,18 */
+	}
+};
+
+static struct scarlett_device_info s18i20_info = {
+	.matrix_in = 18,
+	.matrix_out = 8,
+	.input_len = 18,
+	.output_len = 20,
+
+	.opt_master = {
+		.start = -1,
+		.len = 47,
+		.offsets = {0, 20, 28, 30, 38},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 39,
+		.offsets = {0, 20, 28, 30, 38},
+		.names = NULL
+	},
+
+	.num_controls = 10,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Line 3/4" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "Line 5/6" },
+		{ .num = 3, .type = SCARLETT_OUTPUTS, .name = "Line 7/8" },
+		{ .num = 4, .type = SCARLETT_OUTPUTS, .name = "Line 9/10" },
+		{ .num = 5, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 6, .type = SCARLETT_OUTPUTS, .name = "ADAT 1/2" },
+		{ .num = 7, .type = SCARLETT_OUTPUTS, .name = "ADAT 3/4" },
+		{ .num = 8, .type = SCARLETT_OUTPUTS, .name = "ADAT 5/6" },
+		{ .num = 9, .type = SCARLETT_OUTPUTS, .name = "ADAT 7/8" },
+		/*{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 1, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},*/
+	},
+
+	.matrix_mux_init = {
+		20, 21, 22, 23, 24, 25, 26, 27, /* Analog -> 1..8 */
+		30, 31, 32, 33, 34, 35,     /* ADAT[1..6] -> 9..14 */
+		28, 29,                          /* SPDIF -> 15,16 */
+		0, 1                          /* PCM[1,2] -> 17,18 */
+	}
+};
+
+
+static int scarlett_controls_create_generic(struct usb_mixer_interface *mixer,
+	struct scarlett_device_info *info)
+{
+	int i, err;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	const struct scarlett_mixer_control *ctl;
+	struct usb_mixer_elem_info *elem;
+
+	/* create master switch and playback volume */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_switch,
+			  scarlett_ctl_resume, 0x0a, 0x01, 0,
+			  USB_MIXER_S16, 1, "Master Playback Switch", NULL,
+			  &elem);
+	if (err < 0)
+		return err;
+
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_master,
+			  scarlett_ctl_resume, 0x0a, 0x02, 0,
+			  USB_MIXER_S16, 1, "Master Playback Volume", NULL,
+			  &elem);
+	if (err < 0)
+		return err;
+
+	/* iterate through controls in info struct and create each one */
+	for (i = 0; i < info->num_controls; i++) {
+		ctl = &info->controls[i];
+
+		switch (ctl->type) {
+		case SCARLETT_OUTPUTS:
+			err = add_output_ctls(mixer, ctl->num, ctl->name, info);
+			if (err < 0)
+				return err;
+			break;
+		case SCARLETT_SWITCH_IMPEDANCE:
+			sprintf(mx, "Input %d Impedance Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+					  scarlett_ctl_enum_resume, 0x01,
+					  0x09, ctl->num, USB_MIXER_S16, 1, mx,
+					  &opt_impedance, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case SCARLETT_SWITCH_PAD:
+			sprintf(mx, "Input %d Pad Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+					  scarlett_ctl_enum_resume, 0x01,
+					  0x0b, ctl->num, USB_MIXER_S16, 1, mx,
+					  &opt_pad, &elem);
+			if (err < 0)
+				return err;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Create and initialize a mixer for the Focusrite(R) Scarlett
+ */
+int snd_scarlett_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i, o;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	struct scarlett_device_info *info;
+	struct usb_mixer_elem_info *elem;
+	static char sample_rate_buffer[4] = { '\x80', '\xbb', '\x00', '\x00' };
+
+	/* only use UAC_VERSION_2 */
+	if (!mixer->protocol)
+		return 0;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x1235, 0x8012):
+		info = &s6i6_info;
+		break;
+	case USB_ID(0x1235, 0x8002):
+		info = &s8i6_info;
+		break;
+	case USB_ID(0x1235, 0x8004):
+		info = &s18i6_info;
+		break;
+	case USB_ID(0x1235, 0x8014):
+		info = &s18i8_info;
+		break;
+	case USB_ID(0x1235, 0x800c):
+		info = &s18i20_info;
+		break;
+	default: /* device not (yet) supported */
+		return -EINVAL;
+	}
+
+	/* generic function to create controls */
+	err = scarlett_controls_create_generic(mixer, info);
+	if (err < 0)
+		return err;
+
+	/* setup matrix controls */
+	for (i = 0; i < info->matrix_in; i++) {
+		snprintf(mx, sizeof(mx), "Matrix %02d Input Playback Route",
+			 i+1);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x32,
+				  0x06, i, USB_MIXER_S16, 1, mx,
+				  &info->opt_matrix, &elem);
+		if (err < 0)
+			return err;
+
+		for (o = 0; o < info->matrix_out; o++) {
+			sprintf(mx, "Matrix %02d Mix %c Playback Volume", i+1,
+				o+'A');
+			err = add_new_ctl(mixer, &usb_scarlett_ctl,
+					  scarlett_ctl_resume, 0x3c, 0x00,
+					  (i << 3) + (o & 0x07), USB_MIXER_S16,
+					  1, mx, NULL, &elem);
+			if (err < 0)
+				return err;
+
+		}
+	}
+
+	for (i = 0; i < info->input_len; i++) {
+		snprintf(mx, sizeof(mx), "Input Source %02d Capture Route",
+			 i+1);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x34,
+				  0x00, i, USB_MIXER_S16, 1, mx,
+				  &info->opt_master, &elem);
+		if (err < 0)
+			return err;
+	}
+
+	/* val_len == 1 needed here */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+			  scarlett_ctl_enum_resume, 0x28, 0x01, 0,
+			  USB_MIXER_U8, 1, "Sample Clock Source",
+			  &opt_clock, &elem);
+	if (err < 0)
+		return err;
+
+	/* val_len == 1 and UAC2_CS_MEM */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_sync, NULL, 0x3c, 0x00, 2,
+			  USB_MIXER_U8, 1, "Sample Clock Sync Status",
+			  &opt_sync, &elem);
+	if (err < 0)
+		return err;
+
+	/* initialize sampling rate to 48000 */
+	err = snd_usb_ctl_msg(mixer->chip->dev,
+		usb_sndctrlpipe(mixer->chip->dev, 0), UAC2_CS_CUR,
+		USB_RECIP_INTERFACE | USB_TYPE_CLASS |
+		USB_DIR_OUT, 0x0100, snd_usb_ctrl_intf(mixer->chip) |
+		(0x29 << 8), sample_rate_buffer, 4);
+	if (err < 0)
+		return err;
+
+	return err;
+}
diff --git a/sound/usb/mixer_scarlett.h b/sound/usb/mixer_scarlett.h
new file mode 100644
index 000000000000..19c592ab0332
--- /dev/null
+++ b/sound/usb/mixer_scarlett.h
@@ -0,0 +1,6 @@
+#ifndef __USB_MIXER_SCARLETT_H
+#define __USB_MIXER_SCARLETT_H
+
+int snd_scarlett_controls_create(struct usb_mixer_interface *mixer);
+
+#endif /* __USB_MIXER_SCARLETT_H */
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index c62a1659106d..0d8aba5fe1a8 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -482,6 +482,11 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
 	/* set interface */
 	if (subs->interface != fmt->iface ||
 	    subs->altset_idx != fmt->altset_idx) {
+
+		err = snd_usb_select_mode_quirk(subs, fmt);
+		if (err < 0)
+			return -EIO;
+
 		err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
 		if (err < 0) {
 			dev_err(&dev->dev,
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 83bddbdb90e9..0a598af9b38b 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -2667,57 +2667,6 @@ YAMAHA_DEVICE(0x7010, "UB99"),
 		.type = QUIRK_MIDI_NOVATION
 	}
 },
-{
-	/*
-	 * Focusrite Scarlett 18i6
-	 *
-	 * Avoid mixer creation, which otherwise fails because some of
-	 * the interface descriptor subtypes for interface 0 are
-	 * unknown.  That should be fixed or worked-around but this at
-	 * least allows the device to be used successfully with a DAW
-	 * and an external mixer.  See comments below about other
-	 * ignored interfaces.
-	 */
-	USB_DEVICE(0x1235, 0x8004),
-	.driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
-		.vendor_name = "Focusrite",
-		.product_name = "Scarlett 18i6",
-		.ifnum = QUIRK_ANY_INTERFACE,
-		.type = QUIRK_COMPOSITE,
-		.data = & (const struct snd_usb_audio_quirk[]) {
-			{
-				/* InterfaceSubClass 1 (Control Device) */
-				.ifnum = 0,
-				.type = QUIRK_IGNORE_INTERFACE
-			},
-			{
-				.ifnum = 1,
-				.type = QUIRK_AUDIO_STANDARD_INTERFACE
-			},
-			{
-				.ifnum = 2,
-				.type = QUIRK_AUDIO_STANDARD_INTERFACE
-			},
-			{
-				/* InterfaceSubClass 1 (Control Device) */
-				.ifnum = 3,
-				.type = QUIRK_IGNORE_INTERFACE
-			},
-			{
-				.ifnum = 4,
-				.type = QUIRK_MIDI_STANDARD_INTERFACE
-			},
-			{
-				/* InterfaceSubClass 1 (Device Firmware Update) */
-				.ifnum = 5,
-				.type = QUIRK_IGNORE_INTERFACE
-			},
-			{
-				.ifnum = -1
-			}
-		}
-	}
-},
 
 /* Access Music devices */
 {
@@ -2856,7 +2805,7 @@ AU0828_DEVICE(0x2040, 0x7270, "Hauppauge", "HVR-950Q"),
 		.data = (const struct snd_usb_audio_quirk[]){
 			{
 				.ifnum = 0,
-				.type = QUIRK_IGNORE_INTERFACE,
+				.type = QUIRK_AUDIO_STANDARD_MIXER,
 			},
 			{
 				.ifnum = 1,
@@ -2867,16 +2816,40 @@ AU0828_DEVICE(0x2040, 0x7270, "Hauppauge", "HVR-950Q"),
 					.iface = 1,
 					.altsetting = 1,
 					.altset_idx = 1,
-					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.attributes = 0x4,
 					.endpoint = 0x02,
-					.ep_attr = 0x01,
-					.rates = SNDRV_PCM_RATE_44100 |
-						 SNDRV_PCM_RATE_48000,
-					.rate_min = 44100,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_SYNC,
+					.maxpacksize = 0x130,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
 					.rate_max = 48000,
-					.nr_rates = 2,
+					.nr_rates = 1,
 					.rate_table = (unsigned int[]) {
-						44100, 48000
+						48000
+					}
+				}
+			},
+			{
+				.ifnum = 1,
+				.type = QUIRK_AUDIO_FIXED_ENDPOINT,
+				.data = &(const struct audioformat) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x4,
+					.endpoint = 0x81,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ASYNC,
+					.maxpacksize = 0x130,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
 					}
 				}
 			},
@@ -2884,7 +2857,6 @@ AU0828_DEVICE(0x2040, 0x7270, "Hauppauge", "HVR-950Q"),
 				.ifnum = -1
 			}
 		}
-
 	}
 },
 
@@ -3115,6 +3087,46 @@ AU0828_DEVICE(0x2040, 0x7270, "Hauppauge", "HVR-950Q"),
 
 {
 	/*
+	 * ZOOM R16/24 in audio interface mode.
+	 * Mixer descriptors are garbage, further quirks will be needed
+	 * to make any of it functional, thus disabled for now.
+	 * Playback stream appears to start and run fine but no sound
+	 * is produced, so also disabled for now.
+	 */
+	USB_DEVICE(0x1686, 0x00dd),
+	.driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
+		.ifnum = QUIRK_ANY_INTERFACE,
+		.type = QUIRK_COMPOSITE,
+		.data = (const struct snd_usb_audio_quirk[]) {
+			{
+				/* Mixer */
+				.ifnum = 0,
+				.type = QUIRK_IGNORE_INTERFACE,
+			},
+			{
+				/* Playback  */
+				.ifnum = 1,
+				.type = QUIRK_IGNORE_INTERFACE,
+			},
+			{
+				/* Capture */
+				.ifnum = 2,
+				.type = QUIRK_AUDIO_STANDARD_INTERFACE,
+			},
+			{
+				/* Midi */
+				.ifnum = 3,
+				.type = QUIRK_MIDI_STANDARD_INTERFACE
+			},
+			{
+				.ifnum = -1
+			},
+		}
+	}
+},
+
+{
+	/*
 	 * Some USB MIDI devices don't have an audio control interface,
 	 * so we have to grab MIDI streaming interfaces here.
 	 */
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 60dfe0d28771..4dbfb3d18ee2 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -43,12 +43,13 @@
 static int create_composite_quirk(struct snd_usb_audio *chip,
 				  struct usb_interface *iface,
 				  struct usb_driver *driver,
-				  const struct snd_usb_audio_quirk *quirk)
+				  const struct snd_usb_audio_quirk *quirk_comp)
 {
 	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
+	const struct snd_usb_audio_quirk *quirk;
 	int err;
 
-	for (quirk = quirk->data; quirk->ifnum >= 0; ++quirk) {
+	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
 		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
 		if (!iface)
 			continue;
@@ -58,9 +59,17 @@ static int create_composite_quirk(struct snd_usb_audio *chip,
 		err = snd_usb_create_quirk(chip, iface, driver, quirk);
 		if (err < 0)
 			return err;
-		if (quirk->ifnum != probed_ifnum)
+	}
+
+	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
+		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
+		if (!iface)
+			continue;
+		if (quirk->ifnum != probed_ifnum &&
+		    !usb_interface_claimed(iface))
 			usb_driver_claim_interface(driver, iface, (void *)-1L);
 	}
+
 	return 0;
 }
 
@@ -1102,6 +1111,44 @@ void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 	}
 }
 
+
+/* Marantz/Denon USB DACs need a vendor cmd to switch
+ * between PCM and native DSD mode
+ */
+int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
+			      struct audioformat *fmt)
+{
+	struct usb_device *dev = subs->dev;
+	int err;
+
+	switch (subs->stream->chip->usb_id) {
+	case USB_ID(0x154e, 0x3005): /* Marantz HD-DAC1 */
+	case USB_ID(0x154e, 0x3006): /* Marantz SA-14S1 */
+
+		/* First switch to alt set 0, otherwise the mode switch cmd
+		 * will not be accepted by the DAC
+		 */
+		err = usb_set_interface(dev, fmt->iface, 0);
+		if (err < 0)
+			return err;
+
+		mdelay(20); /* Delay needed after setting the interface */
+
+		switch (fmt->altsetting) {
+		case 2: /* DSD mode requested */
+		case 1: /* PCM mode requested */
+			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
+					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+					      fmt->altsetting - 1, 1, NULL, 0);
+			if (err < 0)
+				return err;
+			break;
+		}
+		mdelay(20);
+	}
+	return 0;
+}
+
 void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep)
 {
 	/*
@@ -1160,6 +1207,14 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
 			break;
 		}
 	}
+
+	/* Zoom R16/24 needs a tiny delay here, otherwise requests like
+	 * get/set frequency return as failed despite actually succeeding.
+	 */
+	if ((le16_to_cpu(dev->descriptor.idVendor) == 0x1686) &&
+	    (le16_to_cpu(dev->descriptor.idProduct) == 0x00dd) &&
+	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
+		mdelay(1);
 }
 
 /*
@@ -1204,5 +1259,16 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
 		break;
 	}
 
+	/* Denon/Marantz devices with USB DAC functionality */
+	switch (chip->usb_id) {
+	case USB_ID(0x154e, 0x3005): /* Marantz HD-DAC1 */
+	case USB_ID(0x154e, 0x3006): /* Marantz SA-14S1 */
+		if (fp->altsetting == 2)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+		break;
+	default:
+		break;
+	}
+
 	return 0;
 }
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index 665e972a1b40..1b862386577d 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -31,6 +31,9 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
 			   __u8 request, __u8 requesttype, __u16 value,
 			   __u16 index, void *data, __u16 size);
 
+int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
+			      struct audioformat *fmt);
+
 u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
 					struct audioformat *fp,
 					unsigned int sample_bytes);
diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c
index a63330dd1407..61d5dc2a3421 100644
--- a/sound/usb/usx2y/usbusx2yaudio.c
+++ b/sound/usb/usx2y/usbusx2yaudio.c
@@ -272,13 +272,8 @@ static void usX2Y_clients_stop(struct usX2Ydev *usX2Y)
 	for (s = 0; s < 4; s++) {
 		struct snd_usX2Y_substream *subs = usX2Y->subs[s];
 		if (subs) {
-			if (atomic_read(&subs->state) >= state_PRERUNNING) {
-				unsigned long flags;
-
-				snd_pcm_stream_lock_irqsave(subs->pcm_substream, flags);
-				snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN);
-				snd_pcm_stream_unlock_irqrestore(subs->pcm_substream, flags);
-			}
+			if (atomic_read(&subs->state) >= state_PRERUNNING)
+				snd_pcm_stop_xrun(subs->pcm_substream);
 			for (u = 0; u < NRURBS; u++) {
 				struct urb *urb = subs->urb[u];
 				if (NULL != urb)