Created attachment 304325 [details] Dmesg logs and Kernel configs of not working backlight and working backlight I did check it by flashlight. Even with all available backlights drivers compiled as modules it does not work. With Kernel version 5.15.106 backlight works fine. Kernels for Chomebook uses dtb files that have some backlight config set (used gpio), like exynos5250-snow-common.dtsi and dmesg of 6.3.4 gives some gpio warnings. Maybe cause in it.
(In reply to Andrew from comment #0) > Created attachment 304325 [details] > Dmesg logs and Kernel configs of not working backlight and working backlight > > I did check it by flashlight. Even with all available backlights drivers > compiled as modules it does not work. With Kernel version 5.15.106 backlight > works fine. > Kernels for Chomebook uses dtb files that have some backlight config set > (used gpio), like exynos5250-snow-common.dtsi and dmesg of 6.3.4 gives some > gpio warnings. Maybe cause in it. Can you perform bisection between 5.15 and 6.3 to find the culprit?
I tried version 6.1.30, backlight works fine. So I decided to check again with version 6.3.4, the backlight works now too. It seems the problem was something other than the kernel. I apologies for the false-positive bug report.