[PATCH] ALSA: compress: allow pause and resume during draining

[Pierre-Louis Bossart]

On 9/28/20 6:13 AM, Jaroslav Kysela wrote:
> Dne 28. 09. 20 v 12:50 Gyeongtaek Lee napsal(a):
>> With a stream with low bitrate, user can't pause or resume the stream
>> near the end of the stream because current ALSA doesn't allow it.
>> If the stream has very low bitrate enough to store whole stream into
>> the buffer, user can't do anything except stop the stream and then
>> restart it from the first.
>> If pause and resume is allowed during draining, user experience can be
>> enhanced.
> 
> It seems that we need a new state to handle the pause + drain condition for
> this case.
> 
> With this proposed change, the pause state in drain is invisible.

Indeed it's be much nicer to have a new state, e..g 
SNDRV_PCM_STATE_DRAINING_PAUSED.

One concern is that states are defined in uapi/sound/asoc.h, so wouldn't 
this have impacts on userspace as well? We'd change the value of 
SNDRV_PCM_STATE_LAST.