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
Fixes: f44f2a5417b2 ("ALSA: compress: fix drain calls blocking other compress functions (v6)") Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org ---
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); }