Messages in this thread | | | Subject | Re: [PATCH v2 1/3] ALSA: compress: document the compress audio state machine | From | Pierre-Louis Bossart <> | Date | Mon, 22 Jun 2020 08:28:48 -0500 |
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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@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..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...
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.
b) no way to go back to SETUP from PREPARE? What happens if the app never starts but want to tear down the resources?
c) no way to stop a paused stream?
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