For a Radeon X600 card, the "ati" driver does not perform fallback, either. lspci excerpt: 0000:01:00.0 VGA compatible controller: ATI Technologies Inc RV370 5B62 [Radeon X600 (PCIE)] 0000:01:00.1 Display controller: ATI Technologies Inc Radeon X600(RV380) (Vendor IDs are 1002:5b62 and 1002:5b72, respectively.)