Hallo, after some investigation I found source of problem (IMHO) at kernel space, brightness is changed for one step, but in user space by gnome-power-manager it is changed for another one step and 1 + 1 = 2 => so brightness is changed twice
Hallo, after some investigation I found source of problem (IMHO)
at kernel space, brightness is changed for one step, but in user space by gnome-power-manager it is changed for another one step and 1 + 1 = 2 => so brightness is changed twice