I found the right log to diagnose this problem (/var/log/gdm/:0.log) and found that xorg was failing when trying to load the ati fglrx graphics drivers. It seems jaunty had removed the drivers only partially. Anyway, I just purged the fglrx drivers and now my video works fine.
** Changed in: xserver-xorg-video-intel (Ubuntu) Status: Confirmed => Invalid -- Blank screen on x4500 after upgrade to Jaunty https://bugs.launchpad.net/bugs/353171 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs