drm/i915: pass the crtc as an argument to intel_fbc_update()

There's no need to reevaluate the status of every single crtc when a
single crtc changes its state.

With this, we're cutting the case where due to a change in pipe B,
intel_fbc_update() is called, then intel_fbc_find_crtc() concludes FBC
should be enabled on pipe A, then it completely rechecks the state of
pipe A only to conclude FBC should remain enabled on pipe A. If any
change on pipe A triggers a need to recompute whether FBC is valid on
pipe A, then at some point someone is going to call
intel_fbc_update(PIPE_A).

The addition of intel_fbc_deactivate() is necessary so we keep track
of the previously selected CRTC when we do invalidate/flush. We're
also going to continue the enable/disable/activate/deactivate concept
in the next patches.

v2: Rebase.
v3: Rebase after changing the patch order.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/

drivers/gpu/drm/i915/intel_display.c

@@ -4792,7 +4792,6 @@ static void intel_post_plane_update(struct intel_crtc *crtc)
 {
 	struct intel_crtc_atomic_commit *atomic = &crtc->atomic;
 	struct drm_device *dev = crtc->base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	if (atomic->wait_vblank)
 		intel_wait_for_vblank(dev, crtc->pipe);
@@ -4806,7 +4805,7 @@ static void intel_post_plane_update(struct intel_crtc *crtc)
 		intel_update_watermarks(&crtc->base);
 
 	if (atomic->update_fbc)
-		intel_fbc_update(dev_priv);
+		intel_fbc_update(crtc);
 
 	if (atomic->post_enable_primary)
 		intel_post_enable_primary(&crtc->base);

drivers/gpu/drm/i915/intel_drv.h

@@ -1323,7 +1323,7 @@ static inline void intel_fbdev_restore_mode(struct drm_device *dev)
 
 /* intel_fbc.c */
 bool intel_fbc_enabled(struct drm_i915_private *dev_priv);
-void intel_fbc_update(struct drm_i915_private *dev_priv);
+void intel_fbc_update(struct intel_crtc *crtc);
 void intel_fbc_init(struct drm_i915_private *dev_priv);
 void intel_fbc_disable(struct drm_i915_private *dev_priv);
 void intel_fbc_disable_crtc(struct intel_crtc *crtc);

drivers/gpu/drm/i915/intel_fbc.c

@@ -429,7 +429,7 @@ static void intel_fbc_schedule_enable(struct intel_crtc *crtc)
 	schedule_delayed_work(&work->work, msecs_to_jiffies(50));
 }
 
-static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
+static void intel_fbc_deactivate(struct drm_i915_private *dev_priv)
 {
 	WARN_ON(!mutex_is_locked(&dev_priv->fbc.lock));
 
@@ -437,6 +437,11 @@ static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
 
 	if (dev_priv->fbc.enabled)
 		dev_priv->fbc.disable_fbc(dev_priv);
+}
+
+static void __intel_fbc_disable(struct drm_i915_private *dev_priv)
+{
+	intel_fbc_deactivate(dev_priv);
 	dev_priv->fbc.crtc = NULL;
 }
 
@@ -501,24 +506,6 @@ static bool crtc_is_valid(struct intel_crtc *crtc)
 	return true;
 }
 
-static struct drm_crtc *intel_fbc_find_crtc(struct drm_i915_private *dev_priv)
-{
-	struct drm_crtc *crtc = NULL, *tmp_crtc;
-	enum pipe pipe;
-
-	for_each_pipe(dev_priv, pipe) {
-		tmp_crtc = dev_priv->pipe_to_crtc_mapping[pipe];
-
-		if (crtc_is_valid(to_intel_crtc(tmp_crtc)))
-			crtc = tmp_crtc;
-	}
-
-	if (!crtc)
-		return NULL;
-
-	return crtc;
-}
-
 static bool multiple_pipes_ok(struct drm_i915_private *dev_priv)
 {
 	enum pipe pipe;
@@ -804,21 +791,28 @@ static bool intel_fbc_hw_tracking_covers_screen(struct intel_crtc *crtc)
 
 /**
  * __intel_fbc_update - enable/disable FBC as needed, unlocked
- * @dev_priv: i915 device instance
+ * @crtc: the CRTC that triggered the update
  *
  * This function completely reevaluates the status of FBC, then enables,
  * disables or maintains it on the same state.
  */
-static void __intel_fbc_update(struct drm_i915_private *dev_priv)
+static void __intel_fbc_update(struct intel_crtc *crtc)
 {
-	struct drm_crtc *drm_crtc = NULL;
+	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
-	struct intel_crtc *crtc;
 	struct drm_framebuffer *fb;
 	struct drm_i915_gem_object *obj;
 	const struct drm_display_mode *adjusted_mode;
 
 	WARN_ON(!mutex_is_locked(&dev_priv->fbc.lock));
 
+	if (!multiple_pipes_ok(dev_priv)) {
+		set_no_fbc_reason(dev_priv, "more than one pipe active");
+		goto out_disable;
+	}
+
+	if (dev_priv->fbc.crtc != NULL && dev_priv->fbc.crtc != crtc)
+		return;
+
 	if (intel_vgpu_active(dev_priv->dev))
 		i915.enable_fbc = 0;
 
@@ -832,18 +826,11 @@ static void __intel_fbc_update(struct drm_i915_private *dev_priv)
 		goto out_disable;
 	}
 
-	drm_crtc = intel_fbc_find_crtc(dev_priv);
+	if (!crtc_is_valid(crtc)) {
-	if (!drm_crtc) {
 		set_no_fbc_reason(dev_priv, "no output");
 		goto out_disable;
 	}
 
-	if (!multiple_pipes_ok(dev_priv)) {
-		set_no_fbc_reason(dev_priv, "more than one pipe active");
-		goto out_disable;
-	}
-
-	crtc = to_intel_crtc(drm_crtc);
 	fb = crtc->base.primary->fb;
 	obj = intel_fb_obj(fb);
 	adjusted_mode = &crtc->config->base.adjusted_mode;
@@ -909,7 +896,8 @@ static void __intel_fbc_update(struct drm_i915_private *dev_priv)
 	 */
 	if (dev_priv->fbc.crtc == crtc &&
 	    dev_priv->fbc.fb_id == fb->base.id &&
-	    dev_priv->fbc.y == crtc->base.y)
+	    dev_priv->fbc.y == crtc->base.y &&
+	    dev_priv->fbc.enabled)
 		return;
 
 	if (intel_fbc_enabled(dev_priv)) {
@@ -955,17 +943,19 @@ static void __intel_fbc_update(struct drm_i915_private *dev_priv)
 
 /*
  * intel_fbc_update - enable/disable FBC as needed
- * @dev_priv: i915 device instance
+ * @crtc: the CRTC that triggered the update
  *
  * This function reevaluates the overall state and enables or disables FBC.
  */
-void intel_fbc_update(struct drm_i915_private *dev_priv)
+void intel_fbc_update(struct intel_crtc *crtc)
 {
+	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
+
 	if (!fbc_supported(dev_priv))
 		return;
 
 	mutex_lock(&dev_priv->fbc.lock);
-	__intel_fbc_update(dev_priv);
+	__intel_fbc_update(crtc);
 	mutex_unlock(&dev_priv->fbc.lock);
 }
 
@@ -991,7 +981,7 @@ void intel_fbc_invalidate(struct drm_i915_private *dev_priv,
 	dev_priv->fbc.busy_bits |= (fbc_bits & frontbuffer_bits);
 
 	if (dev_priv->fbc.busy_bits)
-		__intel_fbc_disable(dev_priv);
+		intel_fbc_deactivate(dev_priv);
 
 	mutex_unlock(&dev_priv->fbc.lock);
 }
@@ -1009,9 +999,9 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv,
 
 	dev_priv->fbc.busy_bits &= ~frontbuffer_bits;
 
-	if (!dev_priv->fbc.busy_bits) {
+	if (!dev_priv->fbc.busy_bits && dev_priv->fbc.crtc) {
-		__intel_fbc_disable(dev_priv);
+		intel_fbc_deactivate(dev_priv);
-		__intel_fbc_update(dev_priv);
+		__intel_fbc_update(dev_priv->fbc.crtc);
 	}
 
 	mutex_unlock(&dev_priv->fbc.lock);