I am using i3 window manager on ubuntu. My laptop has an AMD CPU and integrated GPU and class is amdgpu_bl0. please help me with the command to change the brightness so that I can bind that in config. xbacklight -inc 20% does not work I am getting the error "No outputs have backlight property"
You may have better luck with the tool
light. It works also where
xbacklight doesn't. It is available in the standard ubuntu software repositories of at least version 20.10, so you can install it with
sudo apt install light
If that does not work on your Ubuntu version, you can install it according to the instructions of the application's Github page.
It is a great tool. You can set a minimum brightness so that you will never fully darken the screen. I use it with much satisfaction on the default Ubuntu desktop to increase/decrease the brightness in smaller steps, with the commands
light -U 1 light -A 1