Re: [REGRESSION] amdgpu: thinkpad e495 backlight brightness resets after suspend

[Pierre Asselin <pa@panix.com>]

Alex Deucher <alexdeucher@gmail.com> wrote:

> On Mon, Dec 23, 2024 at 4:08 AM Siva Mahadevan <me@svmhdvn.name> wrote:
> >
> > #regzbot introduced: 99a02eab8
> >
> > Observed behaviour:
> > linux-stable v6.12.5 has a regression on my thinkpad e495 where
> > suspend/resume of the laptop results in my backlight brightness settings
> > to be reset to some very high value. After resume, I'm able to increase
> > brightness further until max brightness, but I'm not able to decrease it
> > anymore.
> >
> > Behaviour prior to regression:
> > linux-stable v6.12.4 correctly maintains the same brightness setting on
> > the backlight that was set prior to suspend/resume.
> >
> > Notes:
> > I bisected this issue between v6.12.4 and v6.12.5 to commit 99a02eab8
> > titled "drm/amdgpu: rework resume handling for display (v2)".
>
> Odd.  That commit shouldn't affect the backlight per se.
>
> >
> > Hardware:
> > * lenovo thinkpad e495
> > * AMD Ryzen 5 3500U with Radeon Vega Mobile Gfx
> > * VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
> >   Picasso/Raven 2 [Radeon Vega Series / Radeon Vega Mobile Series]
> >   (rev c2)
>
> Please file a ticket here:
> https://gitlab.freedesktop.org/drm/amd/-/issues
> and attach your full dmesg output and we'll take a look.
>
> Thanks,
>
> Alex

Alex, Siva: I see the same thing on 6.6.69 .
Hardware:
  HP EliteBook 745 G6
  VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
  Picasso/Raven 2 [Radeon Vega Series / Radeon Vega Mobile Series] (rev d1)

It bisects to 2daba7d857e48035d71cdd95964350b6d0d51545 .
Upstream commit is 73dae652dcac776296890da215ee7dec357a1032 ,
same as in Siva's case.

I'll see if I can create an account at gitlab and file an issue.

I can test patches, preferably off a mainline kernel.
Otherwise, I'll need hand holding with git.

--Pierre Asselin <pa@panix.com>