Comment # 36 on bug 104064 from taijian@posteo.de

Also, here are my backlight devices:

[gunnar@alien-arch ~]$ ls /sys/class/backlight
insgesamt 0
drwxr-xr-x  2 root root 0 12. Mär 18:05 .
drwxr-xr-x 62 root root 0 12. Mär 18:05 ..
lrwxrwxrwx  1 root root 0 12. Mär 18:05 intel_backlight ->
../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight
[gunnar@alien-arch ~]$