ALSA: usb-audio: Add connector notifier delegation

It turned out that ALC1220-VB USB-audio device gives the interrupt
event to some PCM terminals while those don't allow the connector
state request but only the actual I/O terminals return the request.
The recent commit 7dc3c5a0172e ("ALSA: usb-audio: Don't create jack
controls for PCM terminals") excluded those phantom terminals, so
those events are ignored, too.

My first thought was that this could be easily deduced from the
associated terminals, but some of them have even no associate terminal
ID, hence it's not too trivial to figure out.

Since the number of such terminals are small and limited, this patch
implements another quirk table for the simple mapping of the
connectors.  It's not really scalable, but let's hope that there will
be not many such funky devices in future.

Fixes: 7dc3c5a0172e ("ALSA: usb-audio: Don't create jack controls for PCM terminals")
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206873
Link: https://lore.kernel.org/r/20200422113320.26664-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 25 insertions, 0 deletions

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index ecd5036a0b44..a88d7854513b 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -3117,6 +3117,7 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 		if (map->id == state.chip->usb_id) {
 			state.map = map->map;
 			state.selector_map = map->selector_map;
+			mixer->connector_map = map->connector_map;
 			mixer->ignore_ctl_error |= map->ignore_ctl_error;
 			break;
 		}
@@ -3198,10 +3199,32 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 	return 0;
 }
 
+static int delegate_notify(struct usb_mixer_interface *mixer, int unitid,
+			   u8 *control, u8 *channel)
+{
+	const struct usbmix_connector_map *map = mixer->connector_map;
+
+	if (!map)
+		return unitid;
+
+	for (; map->id; map++) {
+		if (map->id == unitid) {
+			if (control && map->control)
+				*control = map->control;
+			if (channel && map->channel)
+				*channel = map->channel;
+			return map->delegated_id;
+		}
+	}
+	return unitid;
+}
+
 void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid)
 {
 	struct usb_mixer_elem_list *list;
 
+	unitid = delegate_notify(mixer, unitid, NULL, NULL);
+
 	for_each_mixer_elem(list, mixer, unitid) {
 		struct usb_mixer_elem_info *info =
 			mixer_elem_list_to_info(list);
@@ -3271,6 +3294,8 @@ static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
 		return;
 	}
 
+	unitid = delegate_notify(mixer, unitid, &control, &channel);
+
 	for_each_mixer_elem(list, mixer, unitid)
 		count++;