Commit 2441bf4d authored by Vinod Koul's avatar Vinod Koul Committed by Takashi Iwai
Browse files

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: default avatarCharles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20200629134737.105993-2-vkoul@kernel.org


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent d7775871

Documentation/sound/designs/compress-offload.rst

+51 −0
Original line number Diff line number Diff line
@@ -151,6 +151,57 @@ 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_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

================