Even with the cumulative set of ilk w/a, rc6 is demonstrably still
failing and causing GPU hangs as found by Peter Wu. So we need to disable
it again until it is stable.
This reverts
commit 456470eb58
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed Aug 8 23:35:40 2012 +0200
drm/i915: enable rc6 on ilk again
and the follow-on
commit cd7988eea5
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Sun Aug 26 20:33:18 2012 +0200
drm/i915: disable rc6 on ilk when vt-d is enabled
Note: The situation around the gen4/5 gpu hangs that cropped up in 3.7
is rather strange. Most useful bisects have lead to
commit 6c085a728c
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon Aug 20 11:40:46 2012 +0200
drm/i915: Track unbound pages
or even later commits that affect the gem bo recycling, which all is
way past the point where we re-enabled rc6. But somehow
reverting/disabling those commits doesn't help, but disabling rc6 at
least helps for many hangs on ilk. Obviously it doesn't change
anything at all on gen4, and there are still strange issues left on
gen5 (which we unfortunately can't readily reproduce).
Also, the error_state signature of the hangs which can be fixed with
this patch look remarkably different to those which seem to be
unaffected by the rc6 settings: The rc6 hangs are in the ring,
somewhere in the MI_FLUSH/PIPE_CONTROL sequence to make ilk coherent,
wheras all the other hangs tend to be at a random point in the middle
of the user batch. So it could also be that we have different issues.
Until we grow more clue, this at least helps some users.
Reported-by: Peter Wu <lekensteyn@gmail.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=55984
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Added note with some more details about the gen4/5 3.7
gpu hang regression.]
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
6567d748c4