Comment 6 for bug 388032

Ah, I have found your problem in your Xorg.0.log.old. You do not have a /etc/X11/xorg.conf which makes xserver use a default detection logic and it has some problems with intel KMS when it is a module in that fbdev tries to take over and crashes the server. it's most likely because intelfb/vesafb is loaded early for the usplash display, and the inteldrmfb gets loaded alot later after thats done.

This has been fixed in debian upstream by this commit which we need to pick up, I added it to xorg-edgers jaunty xserver backport and 3 people have confirmed it fixed it for them in the no xorg.conf situation.
http://git.debian.org/?p=pkg-xorg/xserver/xorg-server.git;a=commit;h=daf26a14473563aa7368c93246f483b11e009d23

To work around this until xorg-server is updated, add this to /etc/X11/xorg.conf and it will work in KMS mode.

Section "Device"
        Identifier "intel"
        Driver "intel"
EndSection