diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 1a06c165a8df..5691dfa1db6f 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1123,17 +1123,21 @@ nv50_mstm_enable(struct nv50_mstm *mstm, u8 dpcd, int state)
 	int ret;
 
 	if (dpcd >= 0x12) {
-		ret = drm_dp_dpcd_readb(mstm->mgr.aux, DP_MSTM_CTRL, &dpcd);
+		/* Even if we're enabling MST, start with disabling the
+		 * branching unit to clear any sink-side MST topology state
+		 * that wasn't set by us
+		 */
+		ret = drm_dp_dpcd_writeb(mstm->mgr.aux, DP_MSTM_CTRL, 0);
 		if (ret < 0)
 			return ret;
 
-		dpcd &= ~DP_MST_EN;
-		if (state)
-			dpcd |= DP_MST_EN;
-
-		ret = drm_dp_dpcd_writeb(mstm->mgr.aux, DP_MSTM_CTRL, dpcd);
-		if (ret < 0)
-			return ret;
+		if (state) {
+			/* Now, start initializing */
+			ret = drm_dp_dpcd_writeb(mstm->mgr.aux, DP_MSTM_CTRL,
+						 DP_MST_EN);
+			if (ret < 0)
+				return ret;
+		}
 	}
 
 	return nvif_mthd(disp, 0, &args, sizeof(args));