There seem to be indeed some awkwards machines around, mostly those
without OpRegion support, where the firmware changes the display hw
state behind our backs when closing the lid.
This force-restore logic has been originally introduced in
commit c1c7af6089
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Thu Sep 10 15:28:03 2009 -0700
drm/i915: force mode set at lid open time
but after the modeset-rework we've disabled it in the vain hope that
it's no longer required:
commit 3b7a89fce3
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Mon Sep 17 22:27:21 2012 +0200
drm/i915: fix OOPS in lid_notify
Alas, no.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54677
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=57434
Tested-by: Krzysztof Mazur <krzysiek@podlesie.net>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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
45e2b5f640