I have recently installed Ubuntu 12.10 with Xubuntu-package on my ASUS U32U notebook (Radeon HD 6320 GPU).
The issue I have is that more often than not, after the GRUB-select screen I get a black screen, and three times total white lines (kind of) flashes very quickly (with maybe 5 seconds between each flash). I'm not even able to get to the login-screen (nor the Xubuntu loading screen).
At first I thought it was simply me having installed something dumb or messed up some settings, but even after reformatting the partition and installing ubuntu again, the problem remains.
Before I formatted it xfce4's window manager wouldn't start either, but it does now (when I am able to see anything).
I can access the virtual console with Ctrl + Alt + F1, but I can't see anything. I've managed to shutdown the computer by using
sudo shutdown -h now