drm/i915: Reset the HEAD pointer for the ring after writing START
authorChris Wilson <chris@chris-wilson.co.uk>
Thu, 7 Aug 2014 14:39:54 +0000 (15:39 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Thu, 4 Sep 2014 09:26:17 +0000 (11:26 +0200)
commit95468892fdfeef6d1004b524e35957629efdbe00
treee4c252187e534b940c9553bd0df70df5d57cd315
parent4ad72b7fadd285f849439cdbc408f8b847cef704
drm/i915: Reset the HEAD pointer for the ring after writing START

Ville found an old w/a documented for g4x that suggested that we need to
reset the HEAD after writing START. This is a useful fixup for some of
the g4x ring initialisation woes, but as usual, not all.

v2: Do the rewrite unconditionally anyway

References: https://bugs.freedesktop.org/show_bug.cgi?id=76554
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: 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>
drivers/gpu/drm/i915/intel_ringbuffer.c