Jake Trent

Adjust Screen Brightness in Arch

In Arch, it’s the little things. Hang on to them. Cherish your ability to do anything. You’ve earned it.

Here’s how to adjust your screen brightness.

Docs

Who doesn’t need help setting up Arch? Arch saves you with some great wiki docs. There’s one on many methods for adjusting screen brightness.

I had no luck with any of the utilities like xbacklight. xrandr --brightness worked, but it only adjusts perceived brightness through color adjustment, not real backlight output.

What follows in the method that worked for me. I have a laptop with an amd gpu.

Adjust with ACPI Hardware

Find out what hardware you have by listing this directory:

ls /sys/class/backlight/

That will show you your graphics card. From there, you can see aspects of the backlight, including:

~ ➜ ls -1 /sys/class/backlight/amdgpu_bl0
actual_brightness
bl_power
brightness
device
max_brightness
power
scale
subsystem
type

Current brightness is in brightness. Min brightness is 0. Max brightness is the value in max_brightness.

Only the root user can adjust the brightness, so switch to be root. I didn’t have any luck adjusting the udev rules to allow non-root adjustment.

Get a root shell by typing su. Then echo the brightness value into the file that you desire.

[root@machine]# echo 100 > /sys/class/backlight/amdgpu_bl0/brightness