drm/i915: fix tiling on IGDNG

It seems that on IGDNG the same swizzling setup always applys.
And front buffer tiling needs to set address swizzle in display
arb control too.

Fix plane tricle feed setting in v1 which should be disable bit,
and always setup address swizzle to let hardware care for buffer
tiling in all cases.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 867a969..d7c7fa4 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1064,6 +1064,10 @@
 			dspcntr &= ~DISPPLANE_TILED;
 	}
 
+	if (IS_IGDNG(dev))
+		/* must disable */
+		dspcntr |= DISPPLANE_TRICKLE_FEED_DISABLE;
+
 	I915_WRITE(dspcntr_reg, dspcntr);
 
 	Start = obj_priv->gtt_offset;
@@ -2719,6 +2723,12 @@
 
 	intel_wait_for_vblank(dev);
 
+	if (IS_IGDNG(dev)) {
+		/* enable address swizzle for tiling buffer */
+		temp = I915_READ(DISP_ARB_CTL);
+		I915_WRITE(DISP_ARB_CTL, temp | DISP_TILE_SURFACE_SWIZZLING);
+	}
+
 	I915_WRITE(dspcntr_reg, dspcntr);
 
 	/* Flush the plane changes */