Brightness Fn+... Doesn't work

Support
1

Cant change brightness settings with keys. When im pressing Fn+F5-F6 the icon about changing brightness is showing up but an actuall brightness is not changing at all.

2

https://wiki.manjaro.org/index.php?title=Forum_Rules#How_to_Post

https://wiki.manjaro.org/index.php?title=Forum_Rules#Common_Sense_Introduction