I've been having this problem on 12.10 with the latest kernel updates for at least three months now but I was hoping that the new (k)ubuntu version would somehow fix it.
If I recall correctly, after updating the kernel from 3.0.5-21 onwards, I get this error upon loading kde:
As you can see the screen area is somehow split in two parts. It kinda cool but not what I wanted!
At first I hoped that it would be fixed (or go away) with the next kernel update but it wasn't!
After testing both kubuntu and ubuntu 13.04 on my system today, I get the same split screen error. What's more there seem to be no install options with the live dvd tests, so the gui is messed up.
I've got a brand new sony vaio (i7, 6GB RAM, with an ATI VGA [Radeon 7500M/7600M Series]).
I've tried to install the "official" ATI linux driver in the past without much success.
It installed allright but couldn't get the 3d acceleration to work so I regressed to the one provided by the repos.
I'm a heavy Blender user and it was hardly possible to use it on such a high end system, which is a same.
I would really really like to make the transition to 13.04 but I guess I need to sort out this damn ati graphics issue first.
My current xorg.conf
Identifier "aticonfig Layout"
Screen 0 "aticonfig-Screen-0" 0 0
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
Option "UseFastTLS" "1"
Viewport 0 0