We need to enable interrupt processing before all the modeset state is set up. But that means we can fall over when we get a pipe underrun. This shouldn't happen as long as the bios works correctly but as usual this turns out to be wishful thinking. So disable error interrupts at irq install time and rely on the re-enabling code in the modeset functions to take care of this. Note that due to the SDE interrupt handling race we must uncondtionally enable all interrupt sources in SDEIER, hence no need to enable the SERR bit specifically. On gmch platforms we don't have an explicit enable/mask bit for fifo underruns. Fixing this up would require a bit of software tracking, hence is material for a separate patch. To make this possible we need to switch all gmch platforms to the new pipestat interrupt handling scheme Imre implemented for vlv, and then also add a safe form of sw state checking to __cpu_fifo_underrun_reporting_enabled a bit. v2: Also handle the ilk/snb cpu fifo underrun bits accordingly. Spotted by Ville. v3: Also handle the south interrupt underrun bits on ibx. Again spotted by Ville. Reported-by: Rob Clark <robdclark@gmail.com> Cc: Rob Clark <robdclark@gmail.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: stable@vger.kernel.org Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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* For the very latest on DRI development, please see: *
* http://dri.freedesktop.org/ *
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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