ALSA Compress API - system suspend/resume

[Daniel Baluta]

On Tue, Oct 4, 2022 at 12:46 PM Pierre-Louis Bossart
<pierre-louis.bossart at linux.intel.com> wrote:
>
> On 10/4/22 11:07 AM, Daniel Baluta wrote:
> > Hello all,
> >
> > It looks like system suspend is not implemented for Compress streams.
> >
> > Any story behind this? Were there any attempts on implementing this?
>
> It depends on the definition of 'system suspend'.
>
> What we had in mind back in the early 2010s was to allow for 'active
> suspend' aka S0ix or low-power playback. That was the main reason for
> introducing the API.
>
> For suspend to S3/D3, the plan was to just completely stop any
> playback/capture and restart on resume. I am not sure if this was ever
> implemented, that may be a miss.

I see. Yes, we are looking at S3/D3 suspend and this doesn't look to
be implemented.

>
> There is a corner case we may have overlooked. I am not sure what
> happens if the S3/D3 suspend while playing. This is supported with e.g.
> aplay but for the compressed case it's a bit more complicated. Not all
> formats support rendering for a random position.

True. We want to implement the same behavior as for aplay. Stop
any playback/capture and restart on resume.

Thanks!