Currently, screen brightness control adjusts the backlight of the display in GNOME. But OLED displays do not have a backlight, and use other methods like PWM or LUT adjustment to control screen brightness.

Surprisingly, GNOME doesn't really have an ideal solution to this problem and by default, in Funtoo GNOME, screen brightness adjustment will not work on OLED.

From the command-line, OLED screen brightness can be adjusted on the Gigabyte Aero 15 as follows:

xrandr --output eDP-1 --brightness 0.5 

This will set the screen brightness to 50%. (range is zero to 1.0).

While GNOME 'nightlight' functionality does work on OLED, I would like to see if we can have something like the redshift package manage all screen brightness/color temperature for GNOME. It is very capable and would allow us to support reduced blue light at night as well as screen brightness and backlight in one place, which I think would be a better architecture than what is currently in GNOME.