drm/atomic: Clean up wait_for_vblanks, v2.

Stop relying on a per crtc_state last_vblank_count, we shouldn't touch
crtc_state after commit. Move it to atomic_state->crtcs.

Also stop re-using new_crtc_state->enable, we can now simply set a
bitmask with crtc_crtc_mask.

Changes since v1:
- Keep last_vblank_count in __drm_crtc_state.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/8e4759a4-24d3-3f80-bd1a-1e7a9c83b612@linux.intel.com
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index c2070bb..d1d678d 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1117,19 +1117,19 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *old_crtc_state;
 	int i, ret;
+	unsigned crtc_mask = 0;
+
+	 /*
+	  * Legacy cursor ioctls are completely unsynced, and userspace
+	  * relies on that (by doing tons of cursor updates).
+	  */
+	if (old_state->legacy_cursor_update)
+		return;
 
 	for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
-		/* No one cares about the old state, so abuse it for tracking
-		 * and store whether we hold a vblank reference (and should do a
-		 * vblank wait) in the ->enable boolean. */
-		old_crtc_state->enable = false;
+		struct drm_crtc_state *new_crtc_state = crtc->state;
 
-		if (!crtc->state->active)
-			continue;
-
-		/* Legacy cursor ioctls are completely unsynced, and userspace
-		 * relies on that (by doing tons of cursor updates). */
-		if (old_state->legacy_cursor_update)
+		if (!new_crtc_state->active)
 			continue;
 
 		if (!drm_atomic_helper_framebuffer_changed(dev,
@@ -1140,16 +1140,16 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
 		if (ret != 0)
 			continue;
 
-		old_crtc_state->enable = true;
-		old_crtc_state->last_vblank_count = drm_crtc_vblank_count(crtc);
+		crtc_mask |= drm_crtc_mask(crtc);
+		old_state->crtcs[i].last_vblank_count = drm_crtc_vblank_count(crtc);
 	}
 
 	for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
-		if (!old_crtc_state->enable)
+		if (!(crtc_mask & drm_crtc_mask(crtc)))
 			continue;
 
 		ret = wait_event_timeout(dev->vblank[i].queue,
-				old_crtc_state->last_vblank_count !=
+				old_state->crtcs[i].last_vblank_count !=
 					drm_crtc_vblank_count(crtc),
 				msecs_to_jiffies(50));