Invalid backlight device choosen
Hello.
I’m using GNOME Wayland on my laptop which (unfortunately) has NVIDIA discrete graphics (RTX2060) - Lenovo 15ARH05H.
The problem is that when I’m using hybrid graphics mode, I get 2 backlight devices:
$ ls /sys/class/backlight
amdgpu_bl0 <-- The correct one
nvidia_0 <-- Chosen by GNOME, but not working
By default, Mutter uses nvidia_0
backlight device which isn’t working. Backlight control works only on the first amdgpu_bl0
device which also drives the display.
The problem disappears when the discrete GPU is disabled there is only 1 backlight control device.
I tried to play with different acpi_backlight
boot arg values but it didn’t help. Then, I tried to find a way to disable the broken backlight device in NVIDIA driver, but NVIDIA removed that option a long time ago (nvidia.NVreg_EnableBacklightHandler=0
and others).
This issue is based on my question on Gnome Discuss, where @carlosg suggested to create an issue here.