Arch Linux

itoet

Member

Registered: 2018-12-06

Posts: 1

Backlight - writing on intel_backlight/brightness does nothing

I have a Clevo N15_17RF with i5-6440HQ + Nvidia 965M. I disabled the GPU with bbswitch. I use the "acpi_osi="!Windows 2015" kernel parameter to fix the lspci hang issue. 

I'm trying to control the brightness of my eDP display. I followed the ArchWiki on backlight with no luck. Writes to /sys/class/backlight/intel_backlight/brightness do nothing unless I write 0 which turns off the display. The maximum brightness is 65535.

Using different "acpi_osi" parameters as suggested in the wiki didn't work, it just creates other issues.

Adding the "acpi_backlight=video" kernel parameter creates the acpi0_video backlight which can't even turn off the light.

The kernel parameter "i915.enable_dpcd_backlight" didn't work, and changing from "intel" drivers to "modesetting" didn't help either.

Any ideas?