drm/i915: enable display messages to GT on ValleyView

Enable the on-chip messaging between the display engine and the GT.

v2: use bit definitions for DPFLIPSTAT reg
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -2653,13 +2653,13 @@
 #define PIPESTAT(pipe) _PIPE(pipe, _PIPEASTAT, _PIPEBSTAT)
 
 #define VLV_DPFLIPSTAT				0x70028
-#define   PIPEB_LINE_COMPARE_STATUS		(1<<29)
+#define   PIPEB_LINE_COMPARE_INT_EN		(1<<29)
 #define   PIPEB_HLINE_INT_EN			(1<<28)
 #define   PIPEB_VBLANK_INT_EN			(1<<27)
 #define   SPRITED_FLIPDONE_INT_EN		(1<<26)
 #define   SPRITEC_FLIPDONE_INT_EN		(1<<25)
 #define   PLANEB_FLIPDONE_INT_EN		(1<<24)
-#define   PIPEA_LINE_COMPARE_STATUS		(1<<21)
+#define   PIPEA_LINE_COMPARE_INT_EN		(1<<21)
 #define   PIPEA_HLINE_INT_EN			(1<<20)
 #define   PIPEA_VBLANK_INT_EN			(1<<19)
 #define   SPRITEB_FLIPDONE_INT_EN		(1<<18)

drivers/gpu/drm/i915/intel_pm.c

@@ -3528,6 +3528,19 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
 
 	I915_WRITE(CACHE_MODE_1,
 		   _MASKED_BIT_ENABLE(PIXEL_SUBSPAN_COLLECT_OPT_DISABLE));
+
+	/*
+	 * On ValleyView, the GUnit needs to signal the GT
+	 * when flip and other events complete.  So enable
+	 * all the GUnit->GT interrupts here
+	 */
+	I915_WRITE(VLV_DPFLIPSTAT, PIPEB_LINE_COMPARE_INT_EN |
+		   PIPEB_HLINE_INT_EN | PIPEB_VBLANK_INT_EN |
+		   SPRITED_FLIPDONE_INT_EN | SPRITEC_FLIPDONE_INT_EN |
+		   PLANEB_FLIPDONE_INT_EN | PIPEA_LINE_COMPARE_INT_EN |
+		   PIPEA_HLINE_INT_EN | PIPEA_VBLANK_INT_EN |
+		   SPRITEB_FLIPDONE_INT_EN | SPRITEA_FLIPDONE_INT_EN |
+		   PLANEA_FLIPDONE_INT_EN);
 }
 
 static void g4x_init_clock_gating(struct drm_device *dev)