Re: [PATCH 1/3] ALSA: compress: document the compress audio state machine

HI Pierre,

On 19-06-20, 09:22, Pierre-Louis Bossart wrote:

...

•                                    +----------+
  

•                                    |          |
  

•                                    |   OPEN   |
  

•                                    |          |
  

•                                    +----------+
  

•                                         |
  

•                                         |
  

•                                         | compr_set_params()
  

•                                         |
  

•                                         V
  

•                                    +----------+
  

•            compr_drain_notify()    |          |
  

•          +------------------------>|   SETUP  |
  

•          |                         |          |
  

•          |                         +----------+
  

•          |                              |
  

•          |                              |
  

•          |                              | compr_write()
  

•          |                              |
  

•          |                              V
  

•          |                         +----------+
  

•          |                         |          |
  

•          |                         |  PREPARE |
  

•          |                         |          |
  

•          |                         +----------+
  

•          |                              |
  

•          |                              |
  

•          |                              | compr_start()
  

•          |                              |
  

•          |                              V
  

•    +----------+                    +----------+     compr_pause()      +----------+
  

•    |          |                    |          |----------------------->|          |
  

•    |  DRAIN   |<-------------------|  RUNNING |                        |  PAUSE   |
  

•    |          |                    |          |<-----------------------|          |
  

•    +----------+                    +----------+     compr_resume()     +----------+
  

•          |                              |
  

•          |                              |
  

•          |                              | compr_free()
  

•          |                              |
  

•          |                              V
  

•          |                         +----------+
  

•          |     compr_free()        |          |
  

•          +------------------------>|          |
  

•                                    |   STOP   |
  

•                                    |          |
  

•                                    +----------+
  

The STOP state doesn't seem quite right to me, sorry.

We should call it free, Will update

the direction of the DRAIN-STOP comp_free() arrow seems wrong? Of if it is correct, then something's missing to exit the STOP state so that the stream can be opened again.

Once stream is freed, it can't be opened again.

But we have trigger stop which is not comprehended here, I will add compr_stop() above which would transition to SETUP state. And a stopped stream can be freed up as well, so one more transition from SETUP to FREE.

Thanks for reviewing