Laptop brightness keys(f3&f4) doesnt work

[BluishHumility]

You can try this other user’s solution, which uses xorg-xbacklight instead of brightnessctl.

I3wm backlight problem

I put my solution here, works on lenovo thinkpad t490s, just in case (for me no need to pression Fn key): sudo pacman -S xorg-xbacklight then added the following to my config file bindsym XF86MonBrightnessUp exec xbacklight -inc 10 bindsym XF86MonBrightnessDown exec xbacklight -dec 10