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

[Pierre-Louis Bossart]

> +
> +                                        +----------+
> +                                        |          |
> +                                        |   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.

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.