On Thu, Aug 03, 2023 at 10:22:07PM +0300, 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@xxxxxxxxx > > 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@xxxxxxx > > 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? Thanks for the regression report. I'm adding it to regzbot: #regzbot ^introduced: 088a40980efbc2 -- An old man doll... just what I always wanted! - Clara
Attachment:
signature.asc
Description: PGP signature
