radeon xorg driver - change mergedfb virtual desktop size on the fly

[Luca Pireddu <lucap@shaw.ca>]

Hello all.  

My laptop has a ATI mobility radeon 9600 which I'm running with the radeon 
xorg driver.  I'd like to be able to change the resolution of my display and 
the size of my desktop by ctrl-alt- +/-.  My goal is to easily change the 
resolution to display the entire desktop with an external projector (and 
cloned on my laptop screen) when needed, then switch back to my normal 
resolution when finished.

At the moment, ctrl-alt- +/- only changes the size of the viewport, so my 
desktop becomes bigger than my screen.  I pasted the relevant lines from 
xorg.conf at the bottom of this email (at least, I think those are the 
relevant ones!)

So how can I make this work the way I'd like?

Thanks in advance

Luca

Section "Device"
  Identifier  "ATI"
  BusID   "PCI:1:0:0"
  Driver    "radeon"
  Option "MergedFB" "on"
  Option "MetaModes" "1280x800 1024x768 800x600 640x480"
EndSection

Section "Screen"
  Identifier  "Default Screen"
  Device    "ATI"
  Monitor   "Laptop Screen"
  DefaultDepth  24
  SubSection "Display"
    Depth   24
    Modes   "1280x800" "1024x768" "800x600" "640x480"
  EndSubSection
EndSection