First, apologies, it works now. It was not that Xorg refused to start, it's just I didn't know that when Xorg starts,
it's not anymore a checkerboard screen but a black one.
So Xorg was in fact working, the problem was the transition from gnome2 to gnome3...gdm2 has not been automaticaly upgraded to gdm3 and it stoped working.
After a manual reinstallation of gnome-core and gdm3, it works.
Clément BRUGUERA <email@example.com> (15/11/2011):
>> After a dist-upgrade last night, xorg refuses to start.
>dist-upgraded from what? If that's just from wheezy/unstable from a
>while ago, what got upgraded? (dpkg.log to the rescue)
It was a dist-upgrade from a one month old testing snapshot to the last testing snapshot.
>> I've tried to disable KMS in /etc/modprobe.d/i915-kms.conf
>KMS has been mandatory for intel for a while now, disabling it can't
>work, especially since you're forcing the driver through xorg.conf
>(which you probably could move aside, since there's nothing interesting
>there except maybe the ZAxisMapping option).
Well, I didn't know that.
>And FWIW, fbdev might be a nice alternative for old cards when intel
Thank you for the time you have lost by replying to this false bug, I'm very sorry for that.