After upgrading to kernel version 5.8 on my Arch Linux machine, backlight controls stopped working for my GeForce GTX 775M Mac Edition. With kernel 5.7.12 and NVIDIA drivers 450.57, everything was working fine. Upgrading to kernel 5.8 and keeping drivers at version 450.57 broke the backlight controls.
I tried changing the backlight in GNOME (running on Xorg, not Wayland) and also by directly writing to
/sys/class/backlight/acpi_video0/brightness. In both cases, the file content is changed successfully, but the backlight stays at full brightness.
I also tried setting the kernel parameter
none, but none of this helped.
The problem still persists with kernel 5.8.9 and drivers 450.66.
I’d be happy to provide more details if needed.
nvidia-bug-report.log.gz (258.9 KB)