drm/i915: Kill intel_flush_primary_plane()

The primary plane frobbing was removed from the sprite code in
 commit ecce87ea3ab55ad0dc64460e6422c357d158a55e
 Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
 Date:   Tue Apr 21 17:12:50 2015 +0300

    drm/i915: Remove implicitly disabling primary plane for now

but the intel_flush_primary_plane() calls were left behind. Replace them
with straight forward POSTING_READ() of the sprite surface address
register.

The other user of intel_flush_primary_plane() is g4x_disable_trickle_feed()
where we can just inline the steps directly.

This allows intel_flush_primary_plane() to be killed off.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -2210,20 +2210,6 @@ static void intel_disable_pipe(struct intel_crtc *crtc)
 		intel_wait_for_pipe_off(crtc);
 }
 
-/*
- * Plane regs are double buffered, going from enabled->disabled needs a
- * trigger in order to latch.  The display address reg provides this.
- */
-void intel_flush_primary_plane(struct drm_i915_private *dev_priv,
-			       enum plane plane)
-{
-	struct drm_device *dev = dev_priv->dev;
-	u32 reg = INTEL_INFO(dev)->gen >= 4 ? DSPSURF(plane) : DSPADDR(plane);
-
-	I915_WRITE(reg, I915_READ(reg));
-	POSTING_READ(reg);
-}
-
 /**
  * intel_enable_primary_hw_plane - enable the primary plane on a given pipe
  * @plane:  plane to be enabled

drivers/gpu/drm/i915/intel_drv.h

@@ -1383,8 +1383,6 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob);
 
 /* intel_sprite.c */
 int intel_plane_init(struct drm_device *dev, enum pipe pipe, int plane);
-void intel_flush_primary_plane(struct drm_i915_private *dev_priv,
-			       enum plane plane);
 int intel_plane_restore(struct drm_plane *plane);
 int intel_sprite_set_colorkey(struct drm_device *dev, void *data,
 			      struct drm_file *file_priv);

drivers/gpu/drm/i915/intel_pm.c

@@ -5886,13 +5886,15 @@ static void ibx_init_clock_gating(struct drm_device *dev)
 static void g4x_disable_trickle_feed(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int pipe;
+	enum pipe pipe;
 
 	for_each_pipe(dev_priv, pipe) {
 		I915_WRITE(DSPCNTR(pipe),
 			   I915_READ(DSPCNTR(pipe)) |
 			   DISPPLANE_TRICKLE_FEED_DISABLE);
-		intel_flush_primary_plane(dev_priv, pipe);
+
+		I915_WRITE(DSPSURF(pipe), I915_READ(DSPSURF(pipe)));
+		POSTING_READ(DSPSURF(pipe));
 	}
 }
 

drivers/gpu/drm/i915/intel_sprite.c

@@ -282,7 +282,6 @@ skl_disable_plane(struct drm_plane *dplane, struct drm_crtc *crtc, bool force)
 
 	I915_WRITE(PLANE_CTL(pipe, plane), 0);
 
-	/* Activate double buffered register update */
 	I915_WRITE(PLANE_SURF(pipe, plane), 0);
 	POSTING_READ(PLANE_SURF(pipe, plane));
 
@@ -339,7 +338,6 @@ vlv_update_plane(struct drm_plane *dplane, struct drm_crtc *crtc,
 	struct drm_device *dev = dplane->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_plane *intel_plane = to_intel_plane(dplane);
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	int pipe = intel_plane->pipe;
 	int plane = intel_plane->plane;
@@ -453,8 +451,7 @@ vlv_update_plane(struct drm_plane *dplane, struct drm_crtc *crtc,
 	I915_WRITE(SPCNTR(pipe, plane), sprctl);
 	I915_WRITE(SPSURF(pipe, plane), i915_gem_obj_ggtt_offset(obj) +
 		   sprsurf_offset);
-
-	intel_flush_primary_plane(dev_priv, intel_crtc->plane);
+	POSTING_READ(SPSURF(pipe, plane));
 }
 
 static void
@@ -463,21 +460,17 @@ vlv_disable_plane(struct drm_plane *dplane, struct drm_crtc *crtc, bool force)
 	struct drm_device *dev = dplane->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_plane *intel_plane = to_intel_plane(dplane);
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_plane->pipe;
 	int plane = intel_plane->plane;
 
 	I915_WRITE(SPCNTR(pipe, plane), 0);
 
-	/* Activate double buffered register update */
 	I915_WRITE(SPSURF(pipe, plane), 0);
-
-	intel_flush_primary_plane(dev_priv, intel_crtc->plane);
+	POSTING_READ(SPSURF(pipe, plane));
 
 	intel_update_sprite_watermarks(dplane, crtc, 0, 0, 0, false, false);
 }
 
-
 static void
 ivb_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		 struct drm_framebuffer *fb,
@@ -489,7 +482,6 @@ ivb_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	struct drm_device *dev = plane->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	enum pipe pipe = intel_plane->pipe;
 	u32 sprctl, sprscale = 0;
@@ -599,8 +591,7 @@ ivb_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	I915_WRITE(SPRCTL(pipe), sprctl);
 	I915_WRITE(SPRSURF(pipe),
 		   i915_gem_obj_ggtt_offset(obj) + sprsurf_offset);
-
-	intel_flush_primary_plane(dev_priv, intel_crtc->plane);
+	POSTING_READ(SPRSURF(pipe));
 }
 
 static void
@@ -609,17 +600,15 @@ ivb_disable_plane(struct drm_plane *plane, struct drm_crtc *crtc, bool force)
 	struct drm_device *dev = plane->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_plane->pipe;
 
 	I915_WRITE(SPRCTL(pipe), I915_READ(SPRCTL(pipe)) & ~SPRITE_ENABLE);
 	/* Can't leave the scaler enabled... */
 	if (intel_plane->can_scale)
 		I915_WRITE(SPRSCALE(pipe), 0);
-	/* Activate double buffered register update */
-	I915_WRITE(SPRSURF(pipe), 0);
 
-	intel_flush_primary_plane(dev_priv, intel_crtc->plane);
+	I915_WRITE(SPRSURF(pipe), 0);
+	POSTING_READ(SPRSURF(pipe));
 }
 
 static void
@@ -633,7 +622,6 @@ ilk_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	struct drm_device *dev = plane->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	int pipe = intel_plane->pipe;
 	unsigned long dvssurf_offset, linear_offset;
@@ -730,8 +718,7 @@ ilk_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	I915_WRITE(DVSCNTR(pipe), dvscntr);
 	I915_WRITE(DVSSURF(pipe),
 		   i915_gem_obj_ggtt_offset(obj) + dvssurf_offset);
-
-	intel_flush_primary_plane(dev_priv, intel_crtc->plane);
+	POSTING_READ(DVSSURF(pipe));
 }
 
 static void
@@ -740,17 +727,14 @@ ilk_disable_plane(struct drm_plane *plane, struct drm_crtc *crtc, bool force)
 	struct drm_device *dev = plane->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_plane->pipe;
 
 	I915_WRITE(DVSCNTR(pipe), 0);
 	/* Disable the scaler */
 	I915_WRITE(DVSSCALE(pipe), 0);
 
-	/* Flush double buffered register updates */
 	I915_WRITE(DVSSURF(pipe), 0);
-
-	intel_flush_primary_plane(dev_priv, intel_crtc->plane);
+	POSTING_READ(DVSSURF(pipe));
 }
 
 static int