Dne 10. 06. 20 v 12:07 Srinivas Kandagatla napsal(a):
For gapless playback call to snd_compr_drain_notify() after
partial drain should put the state to SNDRV_PCM_STATE_RUNNING
rather than SNDRV_PCM_STATE_SETUP as the driver is ready to
process the buffers for new track.
With existing code, if we are playing 3 tracks in gapless, after
partial drain finished on previous track 1 the state is set to
SNDRV_PCM_STATE_SETUP which is then moved to SNDRV_PCM_STATE_PREPARED
after data write. With this state calls to snd_compr_next_track() and
few other calls will fail as they expect the state to be in
SNDRV_PCM_STATE_RUNNING.
Here is the sequence of events and state transitions:
1. set_params (Track 1), state = SNDRV_PCM_STATE_SETUP
2. set_metadata (Track 1), no state change, state = SNDRV_PCM_STATE_SETUP
3. fill and trigger start (Track 1), state = SNDRV_PCM_STATE_RUNNING
4. set_next_track (Track 2), state = SNDRV_PCM_STATE_RUNNING
5. partial_drain (Track 1), state = SNDRV_PCM_STATE_SETUP
6 snd_compr_drain_notify (Track 1), state = SNDRV_PCM_STATE_SETUP
7. fill data (Track 2), state = SNDRV_PCM_STATE_PREPARED
8. set_metadata (Track 3), no state change, state = SNDRV_PCM_STATE_PREPARED
9. set_next_track (Track 3), !! FAILURE as state != SNDRV_PCM_STATE_RUNNING
The snd_compr_drain_notify() is called only from snd_compr_stop(). Something
is missing in this sequence?
Jaroslav
Fixes: f44f2a5417b2 ("ALSA: compress: fix drain calls blocking other compress functions (v6)")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
I wonder who did gapless work on upstream so far?
include/sound/compress_driver.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/sound/compress_driver.h b/include/sound/compress_driver.h
index 6ce8effa0b12..eabac33864c2 100644
--- a/include/sound/compress_driver.h
+++ b/include/sound/compress_driver.h
@@ -182,7 +182,7 @@ static inline void snd_compr_drain_notify(struct snd_compr_stream *stream)
if (snd_BUG_ON(!stream))
return;
- stream->runtime->state = SNDRV_PCM_STATE_SETUP;
+ stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
wake_up(&stream->runtime->sleep);
}
--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
