I currently have three computers running Ubuntu. With two of them, If I don't touch the mouse or keyboard... nothing happens. However, with the third, the screen gets dimmer after about 60 seconds of inactivity. I can't seem to figure out how to prevent this.
I've tried using the control center (gnome-control-center --overview), entering the "Brightness and Lock" screen, and unchecking the "Dim screen to save power" checkbox, but that doesn't actually seem to have any effect on the issue.
I'm running 32-bit Ubuntu 13.04, with the Cinnamon desktop. I also used to have KDE-Plasma, although I decided to get rid of it. Any Ideas?