diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 2b7bb371efee..3553e39a7db4 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1077,6 +1077,14 @@ ieee80211_determine_chan_mode(struct ieee80211_sub_if_data *sdata,
 	const struct cfg80211_bss_ies *ies = rcu_dereference(cbss->ies);
 	struct ieee80211_bss *bss = (void *)cbss->priv;
 	struct ieee80211_channel *channel = cbss->channel;
+	/*
+	 * This is for parsing a beacon or probe response here, but it's
+	 * using the *BSS* elements which are synthetic for multi-BSSID,
+	 * created by cfg80211 based on multi-BSSID inheritance etc. As
+	 * a result, this sets neither .bss (since multi-BSSID is parsed
+	 * already) nor a valid .link_id (since it doesn't want to see
+	 * the data from another link.)
+	 */
 	struct ieee80211_elems_parse_params parse_params = {
 		.link_id = -1,
 		.from_ap = true,