Currently we just make sure vdd is off before suspending, but we don't
cancel the vdd off work. The work wil not touch vdd if
want_panel_vdd==false so in theory this is fine.
In the past that was perfectly fine since the vdd off work didn't do
anything when want_panel_vdd==false, so even if the work would have been
run during system resume before i915 has resumed, nothing would happen.
However since pps_lock() will now grab the power domain references before
it can check want_panel_vdd, we may end up toggling the power wells on/off
already before the driver has resumed. That is not really acceptable, so
cancel the vdd off work when suspending the encoder.
The problem appeared when pps_lock() was introduced in:
commit 773538e860
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Thu Sep 4 14:54:56 2014 +0300
drm/i915: Reset power sequencer pipe tracking when disp2d is off
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
************************************************************
* 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
afa4e53a7b