Comment # 24 on bug 1223838 from Ilgaz Öcal

(In reply to Takashi Iwai from comment #20)
> I backported to TW kernel and Leap 15.6 kernel now.
> 
> Let's keep this entry opened until it's properly merged to the upstream
> tree, though.

on current openSUSE TW 20240531-2933.1 it seems to have merged into kernel
6.9.3

(lspci) 02:00.0 VGA compatible controller: NVIDIA Corporation C79 [GeForce
9400M] (rev b1)

ls -la /sys/class/backlight/
total 0
drwxr-xr-x  2 root root 0 Jun  5 18:12 .
drwxr-xr-x 71 root root 0 Jun  5 18:12 ..
lrwxrwxrwx  1 root root 0 Jun  5 17:41 nv_backlight ->
../../devices/pci0000:00/0000:00:10.0/0000:02:00.0/drm/card0/card0-LVDS-1/nv_backlight