3 changes:
- If a given value is unset, use the maximal limits from the eDP spec.
- Write back the new values, since otherwise the panel power sequencing
hw will not dtrt.
- Revert the early bail-out in case the register values are unset.
The last change reverts
commit bfa3384a9a
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Tue Apr 10 11:58:04 2012 -0700
drm/i915: check PPS regs for sanity when using eDP
v2:
- Unlock the PP regs as the very first thing. This is a required w/a
for cpu eDP on port A, and generally a good idea.
- Fixup the panel power control port selection bits.
v3: Paulo Zanoni noticed that I've fumbled the computation of the spec
limit values. Fix them up. We've also noticed that the t8/t9 values in
the vbt/bios-programmed pp are much larger than any limits. My guess
is that this is to conceal any backlight enable/disable delays. So by
using the much shorter limits from the spec, which only concerns the
sink, we risk that we might display before the backlight is fully on,
or disable the output while the backlight still has afterglow. I've
figured I don't care too much, since this will only happen when both
the pp regs are not programmed, and the vbt tables don't contain
anything useful.
v4: Don't set the port selection bits on hsw/LPT, they don't exist any
more.
v5: Fixup spelling issues in comments, as noticed by Jesse Barnes.
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Paulo Zanoni <paulo.r.zanoni@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
82ed61fa1a