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During suspend we turn off the crtcs, but leave the staged config in place so that we can restore the display(s) to their previous state on resume. During resume when we attempt to apply the force pipe A quirk we use the load detect mechanism. That doesn't check whether there was an already staged configuration for the crtc since that's not even possible during normal runtime load detection. But during resume it is possible, and if we just blindly go and overwrite the staged crtc configuration for the load detection we can no longer restore the display to the correct state. Even worse, we don't even clear all the staged connector->encoder->crtc links so we may end up using a cloned setup for the load detection, and after we're done we just clear the links related to the VGA output leaving the links for the other outputs in place. This will eventually result in calling intel_set_mode() with mode==NULL but with valid connector->encoder->crtc links which will result in dereferencing the NULL mode since the code thinks it will have to a modeset. To avoid these problems don't use any crtc with new_enabled==true for load detection. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org (for 3.16) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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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