All of lore.kernel.org
 help / color / mirror / Atom feed
From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Subject: [PATCH 9/9] ALSA: usb-audio: Avoid killing in-flight URBs during draining
Date: Wed, 29 Sep 2021 10:08:44 +0200	[thread overview]
Message-ID: <20210929080844.11583-10-tiwai@suse.de> (raw)
In-Reply-To: <20210929080844.11583-1-tiwai@suse.de>

While draining a stream, ALSA PCM core stops the stream by issuing
snd_pcm_stop() after all data has been sent out.  And, at PCM trigger
stop, currently USB-audio driver kills the in-flight URBs explicitly,
then at sync-stop ops, sync with the finish of all remaining URBs.
This might result in a drop of the drained samples as most of
USB-audio devices / hosts allow relatively long in-flight samples (as
a sort of FIFO).

For avoiding the trimming, this patch changes the stream-stop behavior
during PCM draining state.  Under that condition, the pending URBs
won't be killed.  The leftover in-flight URBs are caught by the
sync-stop operation that shall be performed after the trigger-stop
operation.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/endpoint.c | 14 +++++++++-----
 sound/usb/endpoint.h |  2 +-
 sound/usb/pcm.c      | 16 ++++++++--------
 3 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 0b336876e36d..42c0d2db8ba8 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -955,7 +955,7 @@ void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
  *
  * This function moves the EP to STOPPING state if it's being RUNNING.
  */
-static int stop_urbs(struct snd_usb_endpoint *ep, bool force)
+static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
 {
 	unsigned int i;
 	unsigned long flags;
@@ -972,6 +972,9 @@ static int stop_urbs(struct snd_usb_endpoint *ep, bool force)
 	ep->next_packet_queued = 0;
 	spin_unlock_irqrestore(&ep->lock, flags);
 
+	if (keep_pending)
+		return 0;
+
 	for (i = 0; i < ep->nurbs; i++) {
 		if (test_bit(i, &ep->active_mask)) {
 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
@@ -995,7 +998,7 @@ static int release_urbs(struct snd_usb_endpoint *ep, bool force)
 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
 
 	/* stop and unlink urbs */
-	err = stop_urbs(ep, force);
+	err = stop_urbs(ep, force, false);
 	if (err)
 		return err;
 
@@ -1527,7 +1530,7 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
 	return 0;
 
 __error:
-	snd_usb_endpoint_stop(ep);
+	snd_usb_endpoint_stop(ep, false);
 	return -EPIPE;
 }
 
@@ -1535,6 +1538,7 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
  *
  * @ep: the endpoint to stop (may be NULL)
+ * @keep_pending: keep in-flight URBs
  *
  * A call to this function will decrement the running count of the endpoint.
  * In case the last user has requested the endpoint stop, the URBs will
@@ -1545,7 +1549,7 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
  * The caller needs to synchronize the pending stop operation via
  * snd_usb_endpoint_sync_pending_stop().
  */
-void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
+void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
 {
 	if (!ep)
 		return;
@@ -1560,7 +1564,7 @@ void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
 	if (!atomic_dec_return(&ep->running)) {
 		if (ep->sync_source)
 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
-		stop_urbs(ep, false);
+		stop_urbs(ep, false, keep_pending);
 	}
 }
 
diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
index 6895d50d14d1..6a9af04cf175 100644
--- a/sound/usb/endpoint.h
+++ b/sound/usb/endpoint.h
@@ -38,7 +38,7 @@ void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
 				   struct snd_usb_substream *data_subs);
 
 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep);
-void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending);
 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep);
 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep);
 int  snd_usb_endpoint_activate(struct snd_usb_endpoint *ep);
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index d5a14e5b9ad3..f09c7380a923 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -219,16 +219,16 @@ int snd_usb_init_pitch(struct snd_usb_audio *chip,
 	return 0;
 }
 
-static bool stop_endpoints(struct snd_usb_substream *subs)
+static bool stop_endpoints(struct snd_usb_substream *subs, bool keep_pending)
 {
 	bool stopped = 0;
 
 	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
-		snd_usb_endpoint_stop(subs->sync_endpoint);
+		snd_usb_endpoint_stop(subs->sync_endpoint, keep_pending);
 		stopped = true;
 	}
 	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
-		snd_usb_endpoint_stop(subs->data_endpoint);
+		snd_usb_endpoint_stop(subs->data_endpoint, keep_pending);
 		stopped = true;
 	}
 	return stopped;
@@ -261,7 +261,7 @@ static int start_endpoints(struct snd_usb_substream *subs)
 	return 0;
 
  error:
-	stop_endpoints(subs);
+	stop_endpoints(subs, false);
 	return err;
 }
 
@@ -437,7 +437,7 @@ static int configure_endpoints(struct snd_usb_audio *chip,
 
 	if (subs->data_endpoint->need_setup) {
 		/* stop any running stream beforehand */
-		if (stop_endpoints(subs))
+		if (stop_endpoints(subs, false))
 			sync_pending_stops(subs);
 		err = snd_usb_endpoint_configure(chip, subs->data_endpoint);
 		if (err < 0)
@@ -572,7 +572,7 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
 	subs->cur_audiofmt = NULL;
 	mutex_unlock(&chip->mutex);
 	if (!snd_usb_lock_shutdown(chip)) {
-		if (stop_endpoints(subs))
+		if (stop_endpoints(subs, false))
 			sync_pending_stops(subs);
 		close_endpoints(chip, subs);
 		snd_usb_unlock_shutdown(chip);
@@ -1559,7 +1559,7 @@ static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substrea
 		return 0;
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
-		stop_endpoints(subs);
+		stop_endpoints(subs, substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING);
 		snd_usb_endpoint_set_callback(subs->data_endpoint,
 					      NULL, NULL, NULL);
 		subs->running = 0;
@@ -1607,7 +1607,7 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 		return 0;
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
-		stop_endpoints(subs);
+		stop_endpoints(subs, false);
 		fallthrough;
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		snd_usb_endpoint_set_callback(subs->data_endpoint,
-- 
2.26.2


      parent reply	other threads:[~2021-09-29  8:12 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-29  8:08 [PATCH 0/9] ALSA: usb-audio: More fixes / improvements on PCM Takashi Iwai
2021-09-29  8:08 ` [PATCH 1/9] ALSA: usb-audio: Restrict rates for the shared clocks Takashi Iwai
2021-09-29  8:08 ` [PATCH 2/9] ALSA: usb-audio: Fix possible race at sync of urb completions Takashi Iwai
2021-09-29  8:08 ` [PATCH 3/9] ALSA: usb-audio: Rename early_playback_start flag with lowlatency_playback Takashi Iwai
2021-09-29  8:08 ` [PATCH 4/9] ALSA: usb-audio: Disable low-latency playback for free-wheel mode Takashi Iwai
2021-09-29  8:08 ` [PATCH 5/9] ALSA: usb-audio: Disable low-latency mode for implicit feedback sync Takashi Iwai
2021-09-29  8:08 ` [PATCH 6/9] ALSA: usb-audio: Check available frames for the next packet size Takashi Iwai
2021-09-29  8:08 ` [PATCH 7/9] ALSA: usb-audio: Add spinlock to stop_urbs() Takashi Iwai
2021-09-29  8:08 ` [PATCH 8/9] ALSA: usb-audio: Improved lowlatency playback support Takashi Iwai
2021-09-29  8:08 ` Takashi Iwai [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210929080844.11583-10-tiwai@suse.de \
    --to=tiwai@suse.de \
    --cc=alsa-devel@alsa-project.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.