Power Management in Xorg
If you let your pc turned on for long periods of time, you should take in consideration the use of the Power Management Features of Xorg, (DPMS) to prevent your LCD or CRT monitor to burn the screen.
How to do it
To enable DPMS, you need to open your favorite editor and go to:
find the Monitor Section and add Option "DPMS" so, it may look something like this:
Section "Monitor" Identifier "My Monitor" HorizSync 31.5 - 57.0 VertRefresh 50-90 Option "DPMS" EndSection
After that you can restart your X server, to do that, just end you current X server session and if kdm is active just restart it pressing Ctrl+Alt+Backspace, after that log in again.
Now you can test the changes with this command:
xset dpms force off
Your screen should go totally off, that means the backlight should go off as well (for LCD monitors).
Next thing is to tell xorg when to turn the screen off, for that you need to edit the same file again, and go to the ServerLayout section and add:
Option "OffTime" "20"
For me, that section looks like this:
Section "ServerLayout" Identifier "Simple Layout" Screen "Screen 1" InputDevice "Mouse1" "CorePointer" InputDevice "Keyboard1" "CoreKeyboard" Option "OffTime" "20" EndSection
Now you are done, after that you can set up your screen saver on kde control center, remember to check the "Make aware of power management" box