disp: msm: dp: check for atomic phase

This change checks for the atomic state and ensures
that allocation and deallocation of vcpi slots is
prevented in the same phase.

Change-Id: I05c87db43eca8ba749ed8a0907dcaf95945dd645
Signed-off-by: Soutrik Mukhopadhyay <[email protected]>

msm/dp/dp_mst_drm.c

@@ -1342,6 +1342,7 @@ static int dp_mst_connector_atomic_check(struct drm_connector *connector,
 		void *display, struct drm_atomic_state *state)
 {
 	int rc = 0, slots, i;
+	bool vcpi_released = false;
 	struct drm_connector_state *old_conn_state;
 	struct drm_connector_state *new_conn_state;
 	struct drm_crtc *old_crtc;
@@ -1416,6 +1417,7 @@ static int dp_mst_connector_atomic_check(struct drm_connector *connector,
 						slots, rc);
 				goto end;
 			}
+			vcpi_released = true;
 		}
 
 		bridge_state->num_slots = 0;
@@ -1461,6 +1463,15 @@ mode_set:
 			goto end;
 		}
 
+		/*
+		 * check if vcpi slots are trying to get allocated in same phase
+		 * as deallocation. If so, go to end to avoid allocation.
+		 */
+		if (vcpi_released) {
+			DP_WARN("skipping allocation since vcpi was released in the same state\n");
+			goto end;
+		}
+
 		if (WARN_ON(bridge_state->num_slots)) {
 			rc = -EINVAL;
 			goto end;