On 11-06-20, 12:40, Jaroslav Kysela wrote: > 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: > > > > > > > > > > > > > > 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? > > > > > > > > > > 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. I completely agree that we should have separate acknowledgements here, and going to rethink all state transitions for gapless here.. Thanks for the help -- ~Vinod
