diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index e8d43d0..098bedc 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -775,7 +775,10 @@
 /**
  * struct ieee80211_mcs_info - MCS information
  * @rx_mask: RX mask
- * @rx_highest: highest supported RX rate
+ * @rx_highest: highest supported RX rate. If set represents
+ *	the highest supported RX data rate in units of 1 Mbps.
+ *	If this field is 0 this value should not be used to
+ *	consider the highest RX data rate supported.
  * @tx_params: TX parameters
  */
 struct ieee80211_mcs_info {