087fbc9962
My Q67 / i7-2600 box has rev09 Sandy Bridge graphics. It hangs instantly when GNOME loads and it hangs so hard the reset button doesn't work. Setting i915.semaphore=0 fixes it. Semaphores were disabled in a1656b9090f7 ("drm/i915: Disable GPU semaphores by default") in 2.6.38 but were then re-enabled (by mistake?) by the merge 47ae63e0c2e5 ("Merge branch 'drm-intel-fixes' into drm-intel-next"). (It's worth noting that the offending change is i915_drv.c, which was not marked as a conflict - although a 'git show --cc' on the merge does show that neither parent had it set to 1) Signed-off-by: Andy Lutomirski <luto@mit.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
************************************************************ * For the very latest on DRI development, please see: * * http://dri.freedesktop.org/ * ************************************************************ The Direct Rendering Manager (drm) is a device-independent kernel-level device driver that provides support for the XFree86 Direct Rendering Infrastructure (DRI). The DRM supports the Direct Rendering Infrastructure (DRI) in four major ways: 1. The DRM provides synchronized access to the graphics hardware via the use of an optimized two-tiered lock. 2. The DRM enforces the DRI security policy for access to the graphics hardware by only allowing authenticated X11 clients access to restricted regions of memory. 3. The DRM provides a generic DMA engine, complete with multiple queues and the ability to detect the need for an OpenGL context switch. 4. The DRM is extensible via the use of small device-specific modules that rely extensively on the API exported by the DRM module. Documentation on the DRI is available from: http://dri.freedesktop.org/wiki/Documentation http://sourceforge.net/project/showfiles.php?group_id=387 http://dri.sourceforge.net/doc/ For specific information about kernel-level support, see: The Direct Rendering Manager, Kernel Support for the Direct Rendering Infrastructure http://dri.sourceforge.net/doc/drm_low_level.html Hardware Locking for the Direct Rendering Infrastructure http://dri.sourceforge.net/doc/hardware_locking_low_level.html A Security Analysis of the Direct Rendering Infrastructure http://dri.sourceforge.net/doc/security_low_level.html