When booting kernel v3.8 in UEFI mode, the screen turns off completely as soon as the 'radeon' module is loaded. dmesg shows these additional lines, compared to a v3.7.9 boot: | radeon 0000:01:00.0: No connectors reported connected with modes | [drm] Cannot find any crtc or sizes - going 1024x768 The connector is definitely connected, since this is a laptop with a built-in screen... (Also different is that the v3.8 log mentions "fence driver on ring 0" and "fence driver on ring 3", whereas the v3.7 log only mentions the ring 0 one.) I'm using an Asus K52JT laptop, with ATi Radeon HD6370M. This only happens when booting in EFI mode (using gummiboot v22 as the bootloader), not in BIOS mode – and only with KMS enabled (doesn't happen when I add "nomodeset" to the kernel command line). The problem was already present when I tried v3.8-rc1; it is not present in any v3.7.x kernel. Assuming I used `git bisect` right, the problem was introduced in: | commit f9a37be0f02a943d63e3346b19f9c9d8d91826cb | Author: Matthew Garrett | Date: Wed Dec 5 14:33:27 2012 -0700 | | x86: Use PCI setup data -- Mantas Mikulėnas