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[2/3] ALSA: compress: document the compress gapless audio state machine

Message ID 20200619045449.3966868-3-vkoul@kernel.org
State Accepted
Commit d0af37c8ec07a1c51920415d61e651c3dc1d6dfb
Headers show
Series ALSA: compress: Document stream states and fix gaplless SM | expand

Commit Message

Vinod Koul June 19, 2020, 4:54 a.m. UTC 
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(+)
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Patch

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
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