Just died after the above problem. You get the X logs which tell you Direct Rendering is working:
(II) I810(0): direct rendering: Enabled
but glxinfo says the contrary:
direct rendering: No
after much searches, I found this thread: http://lists.debian.org/debian-x/2007/01/msg00278.html, which gave me the correct direction: uninstall xorg-driver-fglrx. After that, things would agree again on the fact I have direct rendering.
Now, the question: WTF did I have that useless driver installed?! O_O
