drm/i915: HSW FBC WaFbcAsynchFlipDisableFbcQueue

Display register 420B0h bit 22 must be set to 1b for the entire time that
Frame Buffer Compression is enabled.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
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 10f788b..4e678ba 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -281,6 +281,10 @@
 		I915_WRITE(ILK_DSPCLK_GATE_D,
 			   I915_READ(ILK_DSPCLK_GATE_D) |
 			   ILK_DPFCUNIT_CLOCK_GATE_DISABLE);
+	} else {
+		/* WaFbcAsynchFlipDisableFbcQueue */
+		I915_WRITE(HSW_PIPE_SLICE_CHICKEN_1(intel_crtc->pipe),
+			   HSW_BYPASS_FBC_QUEUE);
 	}
 
 	I915_WRITE(SNB_DPFC_CTL_SA,