drm/i915/fbc: refactor some small functions called only once

The FBC fixes we've been doing in the last months required a lot of
refactor, so functions that were once big and called from different
spots are now small and called only once. IMHO now it's better to just
move the contents of these functions to their only callers since this
reduces the number of indirections while reading the code.

While at it, also improve the related comments a little bit.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453210558-7875-26-git-send-email-paulo.r.zanoni@intel.com

drivers/gpu/drm/i915/intel_fbc.c

@@ -414,14 +414,6 @@ static void intel_fbc_work_fn(struct work_struct *__work)
 	drm_crtc_vblank_put(&crtc->base);
 }
 
-static void intel_fbc_cancel_work(struct drm_i915_private *dev_priv)
-{
-	struct intel_fbc *fbc = &dev_priv->fbc;
-
-	WARN_ON(!mutex_is_locked(&fbc->lock));
-	fbc->work.scheduled = false;
-}
-
 static void intel_fbc_schedule_activation(struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
@@ -436,10 +428,10 @@ static void intel_fbc_schedule_activation(struct intel_crtc *crtc)
 		return;
 	}
 
-	/* It is useless to call intel_fbc_cancel_work() in this function since
-	 * we're not releasing fbc.lock, so it won't have an opportunity to grab
-	 * it to discover that it was cancelled. So we just update the expected
-	 * jiffy count. */
+	/* It is useless to call intel_fbc_cancel_work() or cancel_work() in
+	 * this function since we're not releasing fbc.lock, so it won't have an
+	 * opportunity to grab it to discover that it was cancelled. So we just
+	 * update the expected jiffy count. */
 	work->scheduled = true;
 	work->scheduled_vblank = drm_crtc_vblank_count(&crtc->base);
 	drm_crtc_vblank_put(&crtc->base);
@@ -453,25 +445,15 @@ static void intel_fbc_deactivate(struct drm_i915_private *dev_priv)
 
 	WARN_ON(!mutex_is_locked(&fbc->lock));
 
-	intel_fbc_cancel_work(dev_priv);
+	/* Calling cancel_work() here won't help due to the fact that the work
+	 * function grabs fbc->lock. Just set scheduled to false so the work
+	 * function can know it was cancelled. */
+	fbc->work.scheduled = false;
 
 	if (fbc->active)
 		fbc->deactivate(dev_priv);
 }
 
-static bool crtc_can_fbc(struct intel_crtc *crtc)
-{
-	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
-
-	if (fbc_on_pipe_a_only(dev_priv) && crtc->pipe != PIPE_A)
-		return false;
-
-	if (fbc_on_plane_a_only(dev_priv) && crtc->plane != PLANE_A)
-		return false;
-
-	return true;
-}
-
 static bool multiple_pipes_ok(struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
@@ -831,11 +813,16 @@ static bool intel_fbc_can_choose(struct intel_crtc *crtc)
 		return false;
 	}
 
-	if (!crtc_can_fbc(crtc)) {
+	if (fbc_on_pipe_a_only(dev_priv) && crtc->pipe != PIPE_A) {
 		fbc->no_fbc_reason = "no enabled pipes can have FBC";
 		return false;
 	}
 
+	if (fbc_on_plane_a_only(dev_priv) && crtc->plane != PLANE_A) {
+		fbc->no_fbc_reason = "no enabled planes can have FBC";
+		return false;
+	}
+
 	return true;
 }