mac80211: Disable MCS > 7 in minstrel_ht when STA uses static SMPS

Disable multi stream rates (MCS > 7) when a STA is in static SMPS mode
since it has only one active rx chain. Hence, it doesn't even make
sense to sample multi stream rates.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index ff5f7b84e825..2b42564d6e29 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -692,6 +692,7 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
         int ack_dur;
         int stbc;
         int i;
+        unsigned int smps;
 
         /* fall back to the old minstrel for legacy stations */
         if (!sta->ht_cap.ht_supported)
@@ -731,6 +732,9 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
             oper_chan_type != NL80211_CHAN_HT40PLUS)
                 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 
+        smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >>
+                IEEE80211_HT_CAP_SM_PS_SHIFT;
+
         for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
                 u16 req = 0;
 
@@ -748,6 +752,11 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
                 if ((sta_cap & req) != req)
                         continue;
 
+                /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
+                if (smps == WLAN_HT_CAP_SM_PS_STATIC &&
+                    minstrel_mcs_groups[i].streams > 1)
+                        continue;
+
                 mi->groups[i].supported =
                         mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];