https://bugs.freedesktop.org/show_bug.cgi?id=28402
--- Comment #65 from Alex Deucher agd5f@yahoo.com 2010-09-09 07:36:50 PDT --- The AGPMode xorg option isn't used with kms (the AGP mode is set before X starts when the drm loads). To force a particular AGP mode with kms, use the agpmode module parameter: radeon.agpmode=x where x=-1,1,2,4,8. -1 disables AGP and uses the on-chip gart mechanism instead.