https://bugs.freedesktop.org/show_bug.cgi?id=40576
--- Comment #2 from Alex Deucher agd5f@yahoo.com 2011-09-02 06:58:24 PDT --- Make sure you enable PCI quirks in your kernel. They are needed to access the vbios rom on a lot of cards. Without access to the vbios, the drm can't set up your card.