Comment 49 for bug 615549

Right. So, the underlying problem here appears to be that /dev/fb0, driven by vesafb, gets tagged as PRIMARY_DEVICE_FOR_DISPLAY=1 and gdm is starting on fb0 && PRIMARY_DEVICE_FOR_DISPLAY=1. So gdm is starting before the drm devices are available, and all hell breaks loose.

Reassigning to gdm, as that's what's responsible for prematurely starting X. A safe fix for this would be to replace
"""
...
          and (graphics-device-added fb0 PRIMARY_DEVICE_FOR_DISPLAY=1
               or drm-device-added card0 PRIMARY_DEVICE_FOR_DISPLAY=1
               or stopped udevtrigger))
"""
with
"""
...
         and stopped udevtrigger
"""
from gdm's upstart script. There may be a better way, though, as this will increase boot time.