drm/atomic: add connectors_changed to separate it from mode_changed, v2

This can be a separate case from mode_changed, when connectors stay the
same but only the mode is different. Drivers may choose to implement specific
optimizations to prevent a full modeset for this case.

Changes since v1:
- Update kerneldocs slightly.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 3071319..90a0ff7 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -255,12 +255,13 @@
  * @crtc: backpointer to the CRTC
  * @enable: whether the CRTC should be enabled, gates all other state
  * @active: whether the CRTC is actively displaying (used for DPMS)
- * @mode_changed: for use by helpers and drivers when computing state updates
- * @active_changed: for use by helpers and drivers when computing state updates
+ * @planes_changed: planes on this crtc are updated
+ * @mode_changed: crtc_state->mode or crtc_state->enable has been changed
+ * @active_changed: crtc_state->active has been toggled.
+ * @connectors_changed: connectors to this crtc have been updated
  * @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes
  * @last_vblank_count: for helpers and drivers to capture the vblank of the
  * 	update to ensure framebuffer cleanup isn't done too early
- * @planes_changed: for use by helpers and drivers when computing state updates
  * @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings
  * @mode: current mode timings
  * @event: optional pointer to a DRM event to signal upon completion of the
@@ -283,6 +284,7 @@
 	bool planes_changed : 1;
 	bool mode_changed : 1;
 	bool active_changed : 1;
+	bool connectors_changed : 1;
 
 	/* attached planes bitmask:
 	 * WARNING: transitional helpers do not maintain plane_mask so