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authorTakashi Iwai <tiwai@suse.de>2018-09-13 08:20:43 +0200
committerTakashi Iwai <tiwai@suse.de>2018-10-04 20:13:17 +0200
commit6aea5702e27ebc85747d6e4943a0c378e1752be0 (patch)
treec14ccb05935b7390997e8f4c74a5f4d4b2ab3617 /sound
parentALSA: oxfw: use managed-resource to maintain cache of stream formats (diff)
downloadlinux-6aea5702e27ebc85747d6e4943a0c378e1752be0.tar.xz
linux-6aea5702e27ebc85747d6e4943a0c378e1752be0.zip
ALSA: rawmidi: A lightweight function to discard pending bytes
For discarding the pending bytes on rawmidi, we process with a loop of snd_rawmidi_transmit() which is just a waste of CPU power. Implement a lightweight API function to discard the pending bytes and the proceed the ring buffer instantly, and use it instead of open codes. Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/core/rawmidi.c22
-rw-r--r--sound/core/seq/seq_virmidi.c4
-rw-r--r--sound/usb/midi.c3
3 files changed, 24 insertions, 5 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 08d5662039e3..ee601d7f0926 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -1236,6 +1236,28 @@ int snd_rawmidi_transmit(struct snd_rawmidi_substream *substream,
}
EXPORT_SYMBOL(snd_rawmidi_transmit);
+/**
+ * snd_rawmidi_proceed - Discard the all pending bytes and proceed
+ * @substream: rawmidi substream
+ *
+ * Return: the number of discarded bytes
+ */
+int snd_rawmidi_proceed(struct snd_rawmidi_substream *substream)
+{
+ struct snd_rawmidi_runtime *runtime = substream->runtime;
+ unsigned long flags;
+ int count = 0;
+
+ spin_lock_irqsave(&runtime->lock, flags);
+ if (runtime->avail < runtime->buffer_size) {
+ count = runtime->buffer_size - runtime->avail;
+ __snd_rawmidi_transmit_ack(substream, count);
+ }
+ spin_unlock_irqrestore(&runtime->lock, flags);
+ return count;
+}
+EXPORT_SYMBOL(snd_rawmidi_proceed);
+
static long snd_rawmidi_kernel_write1(struct snd_rawmidi_substream *substream,
const unsigned char __user *userbuf,
const unsigned char *kernelbuf,
diff --git a/sound/core/seq/seq_virmidi.c b/sound/core/seq/seq_virmidi.c
index cb988efd1ed0..e5a40795914a 100644
--- a/sound/core/seq/seq_virmidi.c
+++ b/sound/core/seq/seq_virmidi.c
@@ -149,9 +149,7 @@ static void snd_vmidi_output_work(struct work_struct *work)
/* discard the outputs in dispatch mode unless subscribed */
if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&
!(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {
- char buf[32];
- while (snd_rawmidi_transmit(substream, buf, sizeof(buf)) > 0)
- ; /* ignored */
+ snd_rawmidi_proceed(substream);
return;
}
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index dcfc546d81b9..b737f0ec77d0 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -1175,8 +1175,7 @@ static void snd_usbmidi_output_trigger(struct snd_rawmidi_substream *substream,
if (port->ep->umidi->disconnected) {
/* gobble up remaining bytes to prevent wait in
* snd_rawmidi_drain_output */
- while (!snd_rawmidi_transmit_empty(substream))
- snd_rawmidi_transmit_ack(substream, 1);
+ snd_rawmidi_proceed(substream);
return;
}
tasklet_schedule(&port->ep->tasklet);