Monitor brightness is set to 0% during boot - kernel 6.15.5

[acarstoiu]

I upgraded to kernel 6.15.5 and unfortunately the boot process (OpenRC) is messing with the LCD display brightness.The video card is the one integrated in a rather old AMD APU (Renoir).

Usually, upon start, the brightness would be set to 100% (or so it seems), then when entering my Plasma session the brightness would be adjusted automatically to the last remembered level. Now, after upgrading from kernel 6.15.4 to 6.15.5 the brightness starts at 100% but then, at that point during the boot process when there's a split second of blank screen (some graphics mode change apparently, which I "always" had, with the text font preserving its size and shape), the brightness is dropped at 0%. When I start the Plasma session the brighness remains at 0%, but can be set to whatever I want, starting from the last remembered setting.

The split second of blank screen happens after starting the hwclock service and before starting the modules service. Curiously, these two services are both on the boot runlevel.

Is there a kernel parameter that could prevent this? I temporarily avoid the problem with a tiny script placed in /etc/local.d.

[acarstoiu]

Still no change, kernel 6.17.7 at the moment (gentoo-sources).

[papu]

Still no change, kernel 6.17.7 at the moment (gentoo-sources).

I had this problema with plasma , not remember well but you would try to activate brightness-control to gain control over that stuff , I think is a kde problem rather than kernel (>=plasma 6.2.0)

On the other hand, I'm having a lot of problemes with >6.15.7 kernels and amd drm...something is very buggy

Code: Select all

# equery u powerdevil 
[ Legend : U - final flag setting for installation]
[        : I - package is installed with flag     ]
[ Colors : set, unset                             ]
 * Found these USE flags for kde-plasma/powerdevil-6.5.2:
 U I
 + + brightness-control : Enable screen brightness control using app-misc/ddcutil
 - - debug              : Enable extra debug codepaths, like asserts and extra output. If you want to
                          get meaningful backtraces see
                          https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
 + + filecaps           : Use Linux file capabilities to control privilege rather than set*id (this is
                          orthogonal to USE=caps which uses capabilities at runtime e.g. libcap)
 - - handbook           : Enable handbooks generation for packages by KDE
 - - test               : Enable dependencies and/or preparations necessary to run tests (usually
                          controlled by FEATURES=test but can be toggled independently)

[acarstoiu]

Thanks, but it has nothing to do with KDE Plasma, which isn't even started when the problem occurs.