[alsa-devel] [PATCH] ASoC: Intel: Add support for PM ops in bxt-da7219_max98357a

[Vinod Koul]

On Fri, Jun 17, 2016 at 01:31:56PM +0100, Mark Brown wrote:
> On Fri, Jun 17, 2016 at 05:45:48PM +0530, Vinod Koul wrote:
> > On Fri, Jun 17, 2016 at 01:18:10PM +0200, Lars-Peter Clausen wrote:
> 
> > > Why and why is this something that other cards do not need to do?

Other systems do not have a DSP sitting and need to redownload code which
takes time and results in card being resumed even when the platform is not
ready.

The logs are indicating the snd_soc_resume() is triggered even before the
platform resume has returned which needs to be avoided.

One of the ways to ensure a dependency for PM is resolved, we tinker with PM
callbacks here to ensure the platform is ready before resume is inoked here

> > When card suspends, the DAPM suspend closes the widgets, which translates to
> > we sending IPC to DSP for tearing down the pipelines.
> 
> > So we need the platform to be suspended last and resume first. This way the
> > snd_soc_suspend will tear down pipelines and snd_soc_resume restore those
> > back.
> 
> That doesn't answer the question - this applies to any control
> mechanism.

Thanks
-- 
~Vinod
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