i have ubuntu 12.04 lts and my problem is that whenever i lock ubuntu screen after a minute or so it goes black until i move the mouse or click on the keybored. i disabled screensaver and power saving and every thing but it still goes black only on lock screen. as long as the device is not locked it will not go black.

what i want is to keep my screen on all the time even on lock screen.

can anyone help.