Some machines detect an eDP port even if it's not really there, and eDP
initialization has a fail path for this. Typically such machines have an
LVDS display instead. A regression introduced in
commit 82ed61fa1a
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Sat Oct 20 20:57:41 2012 +0200
drm/i915: make edp panel power sequence setup more robust
updated the power sequence registers PCH_PP_ON_DELAYS, PCH_PP_OFF_DELAYS,
and PCH_PP_DIVISOR also in the ghost eDP case, messing up the LVDS display.
Split the power sequencer initialization into two, delaying the register
updates until after we know the eDP is real.
Note: Keep the PP_CONTROL unlocking in the first part, even if it does not
update registers, per the commit message of the above mentioned commit.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=52601
Reported-and-tested-by: Ryan Coe <ryan@rycomotorsports.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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
f30d26e468