The keys fn+F5 and fn+F6 do not change the brightness on my Asus Zenbook UX305.
I can change the brightness from the command line with this command:
xrandr --output eDP1 --brightness 0.5
This example reduces the brightness to 50% of the rather bright default on the UX305.
But how can I use the default keys (see above) to change the brightness?
Warning: Do not use a brightness value greater than 1.0. Damage to your screen or eyes may result.
Hardware: Asus Zenbook UX305, UX303UA, …
Ubuntu: 14.04, 16.04