Code:
xrandr --current --verbose
Displays Screen 0, DisplayPort-1 and then DP-1-0 through DP-1-4. A piece of Screen 0:
Code:
Screen 0: minimum 320 x 200, current 2560 x 1600, maximum 16384 x 16384eDP connected primary 2560x1600+0+0 (0x57) normal (normal left inverted right x axis y axis) 344mm x 215mm
Identifier: 0x53
Timestamp: 16371083
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Then for
Code:
xrandr --output 0x53 --brightness 0.8
Seems to successfully change brightness.