I'm also affected by this bug. lspci | grep VGA 01:05.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RS780 [Radeon HD 3200] 02:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RV620 LE [Radeon HD 3450] Removing the discrete video card makes the KMS work again. -- Rafał Rutkowski