Linux - hardware and displays
Screen
Managing screen backlight brightness
Discover your backlight device name:
ls /sys/class/backlight/
Get the current brightness (where amdgpu_bl1 is your backlight device name):
cat /sys/class/backlight/amdgpu_bl1/brightness
Get the max brightness:
cat /sys/class/backlight/amdgpu_bl1/max_brightness
Set brightness to 80%:
echo 51811 | sudo tee /sys/class/backlight/amdgpu_bl1/brightness # ~80%
Note: Adaptive Backlight Management (ABM) (“vari-bright”) can sometimes dim the panel independently of this value.