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linux/drivers/gpu/drm
Paulo Zanoni c8a0bd42df drm/i915: send PCI_D3hot adapter opregion message on BDW RPM suspend
On BDW we're seeing a problem that after we runtime resume, the
outputs connected to DDI C are not detected: they don't appear in the
SDEISR register and GMBUS transactions don't work. They stop working
at the moment we call intel_opregion_notify_adapter() during runtime
suspend, but they don't go back to work when we call the same function
during runtime resume. They only work after we do a modeset and call
intel_opregion_notify_encoder(), but this point is already too late.

While debugging, I tried to pass PCI_D3hot which is the value that
matches the spec, and it seems to have solved the problem. I couldn't
find any explanation of why this solves the problem, but there's also
no documented explanation - besides our code and git log - of why
Haswell should use PCI_D1, so keep this for now in order to keep BDW
runtime PM working.

Also add a comment to point the fact that there's no spec documenting
all the weirdness involved here.

Cc: kristen.c.accardi@intel.com
Testcase: igt/pm_rpm/drm-resources-equal
Testcase: igt/pm_rpm/i2c
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-09-03 11:04:23 +02:00
..
2014-08-08 15:57:28 -07:00
2014-07-22 11:31:35 +10:00
2014-08-05 09:41:42 +10:00
2014-07-10 12:01:38 +10:00
2014-09-02 17:28:47 +02:00
2014-07-18 14:24:49 +10:00
2014-08-14 21:24:17 +02:00
2014-08-14 21:24:17 +02:00
2014-07-08 13:03:20 -07:00
2014-08-06 19:10:44 +10:00

************************************************************
* 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