So we had some discussions of the stream states, so I thought it is a good idea to document the state transitions, so add it documentation

Signed-off-by: Vinod Koul vkoul@kernel.org --- .../sound/designs/compress-offload.rst | 52 +++++++++++++++++++ 1 file changed, 52 insertions(+)

diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst index ad4bfbdacc83..7292717c43bf 100644 --- a/Documentation/sound/designs/compress-offload.rst +++ b/Documentation/sound/designs/compress-offload.rst @@ -151,6 +151,58 @@ Modifications include: - Addition of encoding options when required (derived from OpenMAX IL) - Addition of rateControlSupported (missing in OpenMAX AL)

+State Machine +============= + +The compressed audio stream state machine is described below :: + + +----------+ + | | + | OPEN | + | | + +----------+ + | + | + | compr_set_params() + | + V + +----------+ + compr_drain_notify() | | + +------------------------>| SETUP | + | | | + | +----------+ + | | + | | + | | compr_write() + | | + | V + | +----------+ + | | | + | | PREPARE | + | | | + | +----------+ + | | + | | + | | compr_start() + | | + | V + +----------+ +----------+ compr_pause() +----------+ + | | | |----------------------->| | + | DRAIN |<-------------------| RUNNING | | PAUSE | + | | | |<-----------------------| | + +----------+ +----------+ compr_resume() +----------+ + | | + | | + | | compr_free() + | | + | V + | +----------+ + | compr_free() | | + +------------------------>| | + | STOP | + | | + +----------+ +

Gapless Playback ================

Also documented the galpess transitions. Please note that these are not really stream states, but show how the stream steps in gapless mode

Signed-off-by: Vinod Koul vkoul@kernel.org --- .../sound/designs/compress-offload.rst | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+)

diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst index 7292717c43bf..3e241530e173 100644 --- a/Documentation/sound/designs/compress-offload.rst +++ b/Documentation/sound/designs/compress-offload.rst @@ -251,6 +251,38 @@ Sequence flow for gapless would be:

(note: order for partial_drain and write for next track can be reversed as well)

+Gapless Playback SM +=================== + +For Gapless, we move from running state to partial drain and back, along +with setting of meta_data and signalling for next track :: + + + +----------+ + compr_drain_notify() | | + +------------------------>| RUNNING | + | | | + | +----------+ + | | + | | + | | compr_next_track() + | | + | V + | +----------+ + | | | + | |NEXT_TRACK| + | | | + | +----------+ + | | + | | + | | compr_partial_drain() + | | + | V + | +----------+ + | | | + +------------------------ | PARTIAL_ | + | DRAIN | + +----------+

Not supported =============

On partial_drain completion we should be in SNDRV_PCM_STATE_RUNNING state, so set that for partially draining streams in snd_compr_drain_notify() and use a flag for partially draining streams

While at it, add locks for stream state change in snd_compr_drain_notify() as well.

Fixes: f44f2a5417b2 ("ALSA: compress: fix drain calls blocking other compress functions (v6)") Reported-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org Signed-off-by: Vinod Koul vkoul@kernel.org --- include/sound/compress_driver.h | 12 +++++++++++- sound/core/compress_offload.c | 4 ++++ 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/sound/compress_driver.h b/include/sound/compress_driver.h index 3df8d8c90191..93a5897201ea 100644 --- a/include/sound/compress_driver.h +++ b/include/sound/compress_driver.h @@ -66,6 +66,7 @@ struct snd_compr_runtime { * @direction: stream direction, playback/recording * @metadata_set: metadata set flag, true when set * @next_track: has userspace signal next track transition, true when set + * @partial_drain: undergoing partial_drain for stream, true when set * @private_data: pointer to DSP private data * @dma_buffer: allocated buffer if any */ @@ -78,6 +79,7 @@ struct snd_compr_stream { enum snd_compr_direction direction; bool metadata_set; bool next_track; + bool partial_drain; void *private_data; struct snd_dma_buffer dma_buffer; }; @@ -187,7 +189,15 @@ 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; + mutex_lock(&stream->device->lock); + /* for partial_drain case we are back to running state on success */ + if (stream->partial_drain) { + stream->runtime->state = SNDRV_PCM_STATE_RUNNING; + stream->partial_drain = false; /* clear this flag as well */ + } else { + stream->runtime->state = SNDRV_PCM_STATE_SETUP; + } + mutex_unlock(&stream->device->lock);

wake_up(&stream->runtime->sleep); } diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c index e618580feac4..1c4b2cf450a0 100644 --- a/sound/core/compress_offload.c +++ b/sound/core/compress_offload.c @@ -803,6 +803,9 @@ static int snd_compr_stop(struct snd_compr_stream *stream)

retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_STOP); if (!retval) { + /* clear flags and stop any drain wait */ + stream->partial_drain = false; + stream->metadata_set = false; snd_compr_drain_notify(stream); stream->runtime->total_bytes_available = 0; stream->runtime->total_bytes_transferred = 0; @@ -960,6 +963,7 @@ static int snd_compr_partial_drain(struct snd_compr_stream *stream) if (stream->next_track == false) return -EPERM;

+ stream->partial_drain = true; retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_PARTIAL_DRAIN); if (retval) { pr_debug("Partial drain returned failure\n");