Some weeks ago, I've installed an Ubuntu 9.04 on my homemade HTPC based on a Atom 330 and Nvidia ION GPU. I was running nvidia 180 drivers along with XBMC to decode full hd streams using VDPAU hardware acceleration.
This friday, I've updated Ubuntu to 9.10 (karmic), nvidia drivers were automatically updated to the 185 version. I've also updated to the last XBMC version that is supposed to support karmic (9.11~alpha2-karmic1).
Unfortunately, the video playback is not synced to vblank anymore. Viewing anything that moves in these conditions leads to serious headaches.
The only solution I found is to disable compositing (fancy UI effects of the crappy Gnome desktop) by putting this in my xorg.conf file:
Section "Extensions"
Option "Composite" "Disable"
EndSection
The issue is not really solved: the syncing is better but not perfect, the "split" artifact is now at the upper border of the image (approx 5%) and thus is not visible unless I look specifically at it.
So if you have the same setup (ION+ubuntu 9.04+XBMC) do not upgrade to 9.10 as there is currently no XBMC version that is fully compatible without compromises.
