diff --git a/net/wireless/util.c b/net/wireless/util.c
index 3c8be61..935dea9 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1249,7 +1249,7 @@
 	enum cfg80211_chan_mode chmode;
 	int num_different_channels = 0;
 	int total = 1;
-	bool radar_required;
+	bool radar_required = false;
 	int i, j;
 
 	ASSERT_RTNL();
@@ -1264,14 +1264,20 @@
 	case NL80211_IFTYPE_MESH_POINT:
 	case NL80211_IFTYPE_P2P_GO:
 	case NL80211_IFTYPE_WDS:
-		radar_required = !!(chan &&
-				    (chan->flags & IEEE80211_CHAN_RADAR));
+		/* if the interface could potentially choose a DFS channel,
+		 * then mark DFS as required.
+		 */
+		if (!chan) {
+			if (chanmode != CHAN_MODE_UNDEFINED && radar_detect)
+				radar_required = true;
+			break;
+		}
+		radar_required = !!(chan->flags & IEEE80211_CHAN_RADAR);
 		break;
 	case NL80211_IFTYPE_P2P_CLIENT:
 	case NL80211_IFTYPE_STATION:
 	case NL80211_IFTYPE_P2P_DEVICE:
 	case NL80211_IFTYPE_MONITOR:
-		radar_required = false;
 		break;
 	case NUM_NL80211_IFTYPES:
 	case NL80211_IFTYPE_UNSPECIFIED: