drm/atomic: add connector mask to drm_crtc_state.

It can be useful to iterate over connectors without grabbing
connection_mutex. It can also be used to see how many connectors
are on a crtc without iterating over the list.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1451908400-25147-4-git-send-email-maarten.lankhorst@linux.intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 6a21e5c..14b3215 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1063,10 +1063,21 @@
 {
 	struct drm_crtc_state *crtc_state;
 
+	if (conn_state->crtc && conn_state->crtc != crtc) {
+		crtc_state = drm_atomic_get_existing_crtc_state(conn_state->state,
+								conn_state->crtc);
+
+		crtc_state->connector_mask &=
+			~(1 << drm_connector_index(conn_state->connector));
+	}
+
 	if (crtc) {
 		crtc_state = drm_atomic_get_crtc_state(conn_state->state, crtc);
 		if (IS_ERR(crtc_state))
 			return PTR_ERR(crtc_state);
+
+		crtc_state->connector_mask |=
+			1 << drm_connector_index(conn_state->connector);
 	}
 
 	conn_state->crtc = crtc;
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 3b040b3..e3c4d48 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -306,6 +306,7 @@
  * @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
+ * @connector_mask: bitmask of (1 << drm_connector_index(connector)) of attached connectors
  * @last_vblank_count: for helpers and drivers to capture the vblank of the
  * 	update to ensure framebuffer cleanup isn't done too early
  * @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings
@@ -339,6 +340,8 @@
 	 */
 	u32 plane_mask;
 
+	u32 connector_mask;
+
 	/* last_vblank_count: for vblank waits before cleanup */
 	u32 last_vblank_count;