[arch-general] xbacklight, gnome brightness slider don't work, but changing rightness within /sys will

[Alexander Terry]

as per subject, whenever i try to change my brightness with xbacklight
-set, it doesnt work. it does not change the brightness. the same thing
happenes in gnome, with the brightness slider on the top right menu.

what does work is (as root) going into
/sys/class/backlight/intel_backlight, and changing the value in the
brightness folder. there are no other folders in /sys/class/backlight.