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commit01f5a6261cupstream. The VGA_2X_MODE bit apparently affects the display even when the VGA plane is disabled. The bit will set by the BIOS when the panel width is at least 1280 pixels. So by preserving the bit from the BIOS we end up with corrupted display on machines with such high res panels. I only have 1024x768 panels on my gen2 machines so never ran into this problem. The original reason for preserving the VGACNTR register was to make my 830 survive S3 with acpi_sleep=s3_bios option. However after further 830 fixes that option is no longer needed to make S3 work and preserving VGACNTR doesn't seem to be necessary without it, so we can just revert the entire patch. This reverts commit69769f9a42Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Fri Aug 15 01:22:08 2014 +0300 drm/i915: Preserve VGACNTR bits from the BIOS Cc: Bruno Prémont <bonbons@linux-vserver.org> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=87171 Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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