[soder]

Ubuntu 8.10 uses a beta version of Catalyst 8.11 and that works with xorg 7.4. I had the same problem you have there, although only when switching between windowed mode and fullscreen with the \ button. If I start it fullscreen it works for me (try switching the mods when you see that screen). Same mainboard and ati chip. I think the problem might stem from the beta version of Catalyst 8.11 ubuntu is using atm, but I am not sure.

The underscan issue is fixable too - I just for the heck of it can't find the script I used to change the settings with the ati config tool. Try searching phoronix for underscan and ati, I know I found it there.

Edit: - changed overscan to underscan -
Edit2: - found the script -

#!/bin/sh
aticonfig --set-dispattrib=tmds2i,positionX:0
aticonfig --set-dispattrib=tmds2i,positionY:0
aticonfig --set-dispattrib=tmds2i,sizeX:1920
aticonfig --set-dispattrib=tmds2i,sizeY:1080

But I had problems with the Catalyst 8.10 also, now with Ubuntu 8.10 and the Beta Catalyst 8.11 I dont know since my upgrade is not finished. I always start xbmc in fullscreen.

This scrips, will that work for even in 720p? Thats the res. I use. I had underscan for all resulutions, but it looked like the resulution never changed when I changed it in the control center. The screen flashed, but nothing got smaller if you understand what I meen.

/Söder