ALSA: compress: document the compress audio state machine
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
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20200629134737.105993-2-vkoul@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst
index ad4bfbd..ad89af9 100644
--- a/Documentation/sound/designs/compress-offload.rst
+++ b/Documentation/sound/designs/compress-offload.rst
@@ -151,6 +151,57 @@
- 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_write() +----------+ |
+ | | ^ |
+ | | | compr_drain_notify() |
+ | | | or |
+ | | | compr_stop() |
+ | | | |
+ | | +----------+ |
+ | | | | |
+ | | | DRAIN | |
+ | | | | |
+ | | +----------+ |
+ | | ^ |
+ | | | |
+ | | | compr_drain() |
+ | | | |
+ | v | |
+ | +----------+ +----------+ |
+ | | | compr_start() | | compr_stop() |
+ | | PREPARE |------------------->| RUNNING |--------------------------+
+ | | | | | |
+ | +----------+ +----------+ |
+ | | | ^ |
+ | |compr_free() | | |
+ | | compr_pause() | | compr_resume() |
+ | | | | |
+ | v v | |
+ | +----------+ +----------+ |
+ | | | | | compr_stop() |
+ +--->| FREE | | PAUSE |---------------------------+
+ | | | |
+ +----------+ +----------+
+
Gapless Playback
================