drm/i915/bdw: Sampler power bypass disable

BDW-A workaround.

BDW Bug #1899812

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index e036ba0..7e0039e 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5290,6 +5290,8 @@
 	     "GEN8_CENTROID_PIXEL_OPT_DIS not be needed for production\n");
 	I915_WRITE(HALF_SLICE_CHICKEN3,
 		   _MASKED_BIT_ENABLE(GEN8_CENTROID_PIXEL_OPT_DIS));
+	I915_WRITE(HALF_SLICE_CHICKEN3,
+		   _MASKED_BIT_ENABLE(GEN8_SAMPLER_POWER_BYPASS_DIS));
 	I915_WRITE(GAMTARBMODE, _MASKED_BIT_ENABLE(ARB_MODE_BWGTLB_DISABLE));
 
 	/* WaSwitchSolVfFArbitrationPriority */