drm/i915: enable trickle feed on Haswell
We shouldn't disable the trickle feed bits on Haswell. Our
documentation explicitly says the trickle feed bits of PRI_CTL and
CUR_CTL should not be programmed to 1, and the hardware engineer also
asked us to not program the SPR_CTL field to 1. Leaving the bits as 1
could cause underflows.
Reported-by: Arthur Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 78b621c..ad6ec4b 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -260,8 +260,11 @@
if (obj->tiling_mode != I915_TILING_NONE)
sprctl |= SPRITE_TILED;
- /* must disable */
- sprctl |= SPRITE_TRICKLE_FEED_DISABLE;
+ if (IS_HASWELL(dev))
+ sprctl &= ~SPRITE_TRICKLE_FEED_DISABLE;
+ else
+ sprctl |= SPRITE_TRICKLE_FEED_DISABLE;
+
sprctl |= SPRITE_ENABLE;
if (IS_HASWELL(dev))