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kernel 6.9.4-200.fc40.x86_64 starts to slowly blur screen with milky veil when put on battery power; problem immediately solved when plugged in again

  1. Please describe the problem:

When booting 6.9.4-200.fc40.x86_64 and power plugged in on my notebook, everything is fine. But once the power plug is removed so that the notebook switches to battery mode, the screen starts to get slowly blurred as if a "milky veil" is slowly added. So it feels like it gets brighter and brighter, but the brightness does not really change but some other value: simplified, everything gets much whiter than before.

This process takes around 10 seconds until the level of whiteness is achieved that remains. It is still possible to work that way, although things look a little strange.

Once I plug in power again, it takes about a second, and then immediately (without any delay), the picture is normal again.

I can change brightness and day/night mode as usual, but the "whiteness" effect remains if I do that while on battery. The settings have not changed, including the battery/plugged-in settings.

When I boot 6.8.11, the problem does not appear.

  1. What is the Version-Release number of the kernel / Hardware description / System information:

The affected one: Linux fedora 6.9.4-200.fc40.x86_64 #1 (closed) SMP PREEMPT_DYNAMIC

I use Fedora 40 KDE Spin. Tainted = 0. Only default repositories of Fedora except vlc and its dependencies (I limited rpmfusion to the very packages; other updates are taken solely from default repos).

AMD Ryzen 7 PRO 6850U with Radeon Graphics (only internal graphics: Advanced Micro Devices, Inc. [AMD/ATI] Rembrandt [Radeon 680M]). I use the SELinux profile sysadm_u (confined user) with the x boolean enabled while working (this has been the case without related issues since Jan 2023).

  1. Did it work previously in Fedora?:

The problem occurred first with 6.9.4-200.fc40.x86_64. 6.8.11 works fine.

  1. Can you reproduce this issue? If so, please provide the steps to reproduce the issue below:

1st) Just boot the kernel 6.9.4-200.fc40.x86_64 on Lenovo T16 Gen1, AMD Ryzen 7 PRO 6850U with Radeon Graphics.
2d) Plug off power and watch the subsequent 10 seconds for the "milky white" to come.
3rd) Plug on power again and wait about 1 second, then the "milky white" is completely gone immediately.

  1. Does this problem occur with the latest Rawhide kernel? To install the Rawhide kernel, run sudo dnf install fedora-repos-rawhide followed by sudo dnf update --enablerepo=rawhide kernel:

Rawhide not tested. Just 6.9.4 as newest kernel, and 6.8.11.

  1. Are you running any modules that not shipped with directly Fedora's kernel?:

No. cat /proc/sys/kernel/tainted = 0.

  1. Please attach the kernel logs. You can get the complete kernel log for a boot with journalctl --no-hostname -k > dmesg.txt. If the issue occurred on a previous boot, use the journalctl -b flag.

I have created a dedicated boot, once with 6.9.4 that contains the issue, and once with 6.8.11 that contains no problems.

The log of the problem with 6.9.4 is here: https://gitlab.com/py0xc3/tmp_8dc37e8453bbfbd61ad1/-/blob/main/kernel6.9.4/6.9.4-200.screenChanges.log -> I plugged off power on 19:03:50 system time (then the issue started until it reached the highest "milky" factor after around 10 seconds), and then I plugged in power again on 19:04:20 (after about 1 second, everything was fine again).

On 6.8.11, everything is fine: https://gitlab.com/py0xc3/tmp_8dc37e8453bbfbd61ad1/-/blob/main/kernel6.9.4/6.8.11-300.screenNormal.log -> I plugged of power on 19:01:00 and plugged power in again on 19:01:40: everything fine, no issues.

Issue is reproducible always.

I opened another ticket downstream about s2idle, but although the other issue started to occur with the update that also introduced 6.9.4 (which was the update with which I introduced 6.9 and thus 6.9 headers and such), it now affects 6.8.11 and 6.8.10. So I guess these are not related. However, if you want to review: https://bugzilla.redhat.com/show_bug.cgi?id=2292520 (I will file that one here as well and add a post with the ticket below)

Thanks for taking care. Let me know if you need more.

Reproducible: Always

Edited by Chris