On 22-06-20, 08:28, Pierre-Louis Bossart wrote: > > > On 6/22/20 1:58 AM, Vinod Koul wrote: > > 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@xxxxxxxxxx> > > --- > > .../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..6f86db82298b 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_free() +----------+ > > + +-------------------------------------| | > > + | | SETUP | > > + | +------------------------>| |<---------------------------------+ > > + | | compr_drain_notify() +----------+ | > > + | | | | > > + | | | | > > + | | | compr_write() | > > + | | | | > > + | | v | > > + | | +----------+ | > > + | | | | | > > + | | | PREPARE | | > > + | | | | | > > + | | +----------+ | > > + | | | | > > + | | | | > > + | | | compr_start() | > > + | | | | > > + | | v | > > + | +----------+ +----------+ compr_pause() +----------+ | > > + | | | compr_drain() | |---------------->| | | > > + | | DRAIN |<-------------------| RUNNING | | PAUSE | | > > + | | | | |<----------------| | | > > + | +----------+ +----------+ compr_resume() +----------+ | > > + | | | | | > > + | | | | | > > + | | | | | > > + | | | | compr_stop() | > > + | | | +------------------------------------+ > > + | | +----------+ | > > + | | | | | > > + +-----------+------>| |<-------+ > > + compr_free() | FREE | compr_free() > > + | | > > + +----------+ > > + > > Sorry, this confuses me even more... Oops > a) can you clarify if we can go from running to free directly? is this > really a legit transition? There's already the option of doing a stop and a > a drain. As Charles pointed it is legit one, but then from SM we should remove running->free arrow to clarify. Internally, free in running, draining and paused triggers a stop and then free. > b) no way to go back to SETUP from PREPARE? What happens if the app never > starts but want to tear down the resources? See above, free would trigger an internal step to stop (setup) and then freed. Btw I am not adding changes to code but documenting the 'existing' behaviour, so a code lookup will help > c) no way to stop a paused stream? Yes missed that, will add. -- ~Vinod
