drm/i915: Clear VLV_IIR after PIPESTAT
authorVille Syrjälä <ville.syrjala@linux.intel.com>
Wed, 13 Apr 2016 18:19:49 +0000 (21:19 +0300)
committerVille Syrjälä <ville.syrjala@linux.intel.com>
Thu, 14 Apr 2016 11:45:15 +0000 (14:45 +0300)
commit7ce4d1f2730f2bd4320425dd376913c4a12bd3b2
treeec3f0b65a08485007711f27f079d2b537d95171b
parent34c7b8a7b8b5a2075b37654aa2d1a46b1cee9ef2
drm/i915: Clear VLV_IIR after PIPESTAT

On VLV/CHV VLV_IIR is not double double buffered, and it doesn't detect
edges from PIPESTAT & co. like it does on gen4. Instead it just
directly latches the level from PIPESTAT & co. That means we must clear
VLV_IIR after PIPESTAT & co. or else we'll get a spurious bit in VLV_IIR
every single time.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1460571598-24452-4-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
drivers/gpu/drm/i915/i915_irq.c