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()|vcompr_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?