3 files changed, 24 insertions, 4 deletions

diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 707c5b418dc6..124dfedb0fd1 100644
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -407,9 +407,17 @@ static inline void ath9k_htc_err_stat_rx(struct ath9k_htc_priv *priv,
 #define MIN_SWBA_RESPONSE     10 /* in TUs */
 
 struct htc_beacon {
+        enum {
+                OK,             /* no change needed */
+                UPDATE,         /* update pending */
+                COMMIT          /* beacon sent, commit change */
+        } updateslot;           /* slot time update fsm */
+
         struct ieee80211_vif *bslot[ATH9K_HTC_MAX_BCN_VIF];
         u32 bmisscnt;
         u32 beaconq;
+        int slottime;
+        int slotupdate;
 };
 
 struct ath_btcoex {
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index 4b3b4dd49a42..8a3bd5fe3a54 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -520,6 +520,7 @@ static int ath9k_init_priv(struct ath9k_htc_priv *priv,
 
         for (i = 0; i < ATH9K_HTC_MAX_BCN_VIF; i++)
                 priv->beacon.bslot[i] = NULL;
+        priv->beacon.slottime = ATH9K_SLOT_TIME_9;
 
         ath9k_cmn_init_channels_rates(common);
         ath9k_cmn_init_crypto(ah);
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index b82a7c43eb6e..f46cd0250e48 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -1500,6 +1500,7 @@ static void ath9k_htc_bss_info_changed(struct ieee80211_hw *hw,
         struct ath9k_htc_priv *priv = hw->priv;
         struct ath_hw *ah = priv->ah;
         struct ath_common *common = ath9k_hw_common(ah);
+        int slottime;
 
         mutex_lock(&priv->mutex);
         ath9k_htc_ps_wakeup(priv);
@@ -1575,11 +1576,21 @@ static void ath9k_htc_bss_info_changed(struct ieee80211_hw *hw,
 
         if (changed & BSS_CHANGED_ERP_SLOT) {
                 if (bss_conf->use_short_slot)
-                        ah->slottime = 9;
+                        slottime = 9;
                 else
-                        ah->slottime = 20;
-
-                ath9k_hw_init_global_settings(ah);
+                        slottime = 20;
+                if (vif->type == NL80211_IFTYPE_AP) {
+                        /*
+                         * Defer update, so that connected stations can adjust
+                         * their settings at the same time.
+                         * See beacon.c for more details
+                         */
+                        priv->beacon.slottime = slottime;
+                        priv->beacon.updateslot = UPDATE;
+                } else {
+                        ah->slottime = slottime;
+                        ath9k_hw_init_global_settings(ah);
+                }
         }
 
         if (changed & BSS_CHANGED_HT)