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c7dffff7cc
We learned that the ECOBUS register was inside the GT power well, and so *did* need force wake to be read, so it gets removed from the list of 'doesn't need force wake' registers. That means the code reading ECOBUS after forcing the mt_force_wake function to be called needs to use I915_READ_NOTRACE; it doesn't need to do more force wake fun as it's already done it manually. This also adds a comment explaining why the MT forcewake testing code only needs to call mt_forcewake_get/put and not disable RC6 manually -- the ECOBUS read will return 0 if the device is in RC6 and isn't using MT forcewake, causing the test to work correctly. Signed-off-by: Keith Packard <keithp@keithp.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
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* 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