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,