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a1656b9090
Andi Kleen narrowed his GPU hangs on his Sugar Bay (SNB desktop) rev 09 down to the use of GPU semaphores, and we already know that they appear broken up to Huron River (mobile) rev 08. (I'm optimistic that disabling GPU semaphores is simply hiding another bug by the latency and side-effects of the additional device interaction it introduces...) However, use of semaphores is a massive performance improvement... Only as long as the system remains stable. Enable at your peril. Reported-by: Andi Kleen <andi-fd@firstfloor.org> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33921 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
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* For the very latest on DRI development, please see: *
* http://dri.freedesktop.org/ *
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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