I'm trying to change the brightness of my screen in Ubuntu 18.04 pressing the keyboard Fn+F4 and Fn+F5 keys, but it's freezing all keyboard input, then changing brightness to max (Fn+F5) or min (Fn+F4). I searched in google for a solution and I was not successful. I have just a clue of the problem, that I found using the following command:
I got the following log:
Ps.: I can change the brightness by gnome's interface using the mouse normally.