Dne 11. 06. 20 v 11:44 Vinod Koul napsal(a):
On 11-06-20, 11:09, Jaroslav Kysela wrote:
Dne 11. 06. 20 v 10:46 Charles Keepax napsal(a):
On Wed, Jun 10, 2020 at 04:28:20PM +0530, Vinod Koul wrote:
On 10-06-20, 12:40, Jaroslav Kysela wrote:
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:
- set_params (Track 1), state = SNDRV_PCM_STATE_SETUP
- set_metadata (Track 1), no state change, state = SNDRV_PCM_STATE_SETUP
- fill and trigger start (Track 1), state = SNDRV_PCM_STATE_RUNNING
- set_next_track (Track 2), state = SNDRV_PCM_STATE_RUNNING
- 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?
It is supposed to be invoked by driver when partial drain is complete.. both intel and sprd driver are calling this. snd_compr_stop is stop while draining case so legit
Not sure I follow this statement, could you elaborate a bit? snd_compr_stop putting the state to RUNNING seems fundamentally broken to me, the whole point of snd_compr_stop is to take the state out of RUNNING.
Yes. I agree. It seems that the acknowledge for the partial drain should be handled differently.
Yeah sorry I overlooked that case and was thinking of it being invoked from driver!
Yes this would make the snd_compr_stop() behave incorrectly.. so this cant be done as proposed.
But we still need to set the draining stream state properly and I am thinking below now:
diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c index 509290f2efa8..9aba851732d7 100644 --- a/sound/core/compress_offload.c +++ b/sound/core/compress_offload.c @@ -929,7 +929,9 @@ static int snd_compr_partial_drain(struct snd_compr_stream *stream) }
stream->next_track = false;
return snd_compress_wait_for_drain(stream);
retval = snd_compress_wait_for_drain(stream);stream->runtime->state = SNDRV_PCM_STATE_RUNNING;return retval;
I see a race possibility when the last track is too small and the driver signals the end-of-track twice. In this case the partial drain should not end with the running state. It would be probably better to separate partial / last track acknowledgements.
Jaroslav