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