Re: Regression apparently caused by commit 088a40980efbc2c449b72f0f2c7ebd82f71d08e2 "ASoC: amd: acp: add pm ops support for acp pci driver"

[syed saba kareem <ssabakar@amd.com>]

On 8/4/23 00:52, Marian Postevca wrote:
> I'm trying to develop a sound machine driver based on the acp legacy driver.
> The first version of the driver was sent for review on the alsa mailing list this
> spring: https://lore.kernel.org/all/20230320203519.20137-1-posteuca@mutex.one
>
> I'm trying to fix some of the issues that were brought up during the review back then,
> but when I ported the patches to the latest commit on the for-next
> branch, I noticed a regression where I couldn't hear any sound at all.
>
> So I started a bisect session and found that the first bad commit is:
> ASoC: amd: acp: add pm ops support for acp pci driver
> commit 088a40980efbc2c449b72f0f2c7ebd82f71d08e2
> https://lore.kernel.org/lkml/20230622152406.3709231-11-Syed.SabaKareem@amd.com
>
> If I revert this commit sound works as expected. So I started tinkering a little bit
> with it and I believe that what happens is that the acp pci driver
> enters the autosuspend state and never leaves this state at all.
> I noticed this because if I increase the autosuspend delay to a much
> larger value, then the sound works until that delay passes.
> I added traces and I can see that when the delay expires the suspend callback snd_acp_suspend()
> gets called, but the resume callback snd_acp_resume() never gets called.
>
> I'm no expert in runtime power management (though I did read a bit on it), so I don't understand
> all the things that happen underneath, but one thing that is not clear to me is who's supposed
> to mark activity on this device and keep it from entering autosuspend if the user wants to play
> some sound? Shouldn't there be some counterpart that calls pm_runtime_mark_last_busy() ?
> I looked through the code and can't find who's calling pm_runtime_mark_last_busy().
>
> Some help here would be welcome. Is there something missing in my machine driver code, or
> is the runtime pm handling in acp pci driver wrong?

We haven't up streamed pm ops for Renoir platform.

That is the cause for the issue.

Will upstream them in a week.