We have been setting the bit which was originally BIOS dependent since:
commit f05bb0c7b6
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Sun Jan 20 16:33:32 2013 +0000
drm/i915: GFX_MODE Flush TLB Invalidate Mode must be '1' for scanline waits
Therefore, we do not need to try to figure it out dynamically and we can
just always invalidate the TLBs.
It's a partial revert of:
commit 12b0286f49
Author: Ben Widawsky <ben@bwidawsk.net>
Date: Mon Jun 4 14:42:50 2012 -0700
drm/i915: possibly invalidate TLB before context switch
The original commit attempted to only invalidate when necessary
(very much a relic from the old days). Now, we can just always invalidate.
I guess the old TODO still exists. Since we seem to have abandoned ILK
contexts however, there isn't much point in even remembering.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
************************************************************
* 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
057f6a8ad7