diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index fcfa1bf..8c35418 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1318,6 +1318,50 @@
 }
 #endif
 
+int __ieee80211_request_smps(struct ieee80211_sub_if_data *sdata,
+			     enum ieee80211_smps_mode smps_mode)
+{
+	const u8 *ap;
+	enum ieee80211_smps_mode old_req;
+	int err;
+
+	old_req = sdata->u.mgd.req_smps;
+	sdata->u.mgd.req_smps = smps_mode;
+
+	if (old_req == smps_mode &&
+	    smps_mode != IEEE80211_SMPS_AUTOMATIC)
+		return 0;
+
+	/*
+	 * If not associated, or current association is not an HT
+	 * association, there's no need to send an action frame.
+	 */
+	if (!sdata->u.mgd.associated ||
+	    sdata->local->oper_channel_type == NL80211_CHAN_NO_HT) {
+		mutex_lock(&sdata->local->iflist_mtx);
+		ieee80211_recalc_smps(sdata->local, sdata);
+		mutex_unlock(&sdata->local->iflist_mtx);
+		return 0;
+	}
+
+	ap = sdata->u.mgd.associated->cbss.bssid;
+
+	if (smps_mode == IEEE80211_SMPS_AUTOMATIC) {
+		if (sdata->u.mgd.powersave)
+			smps_mode = IEEE80211_SMPS_DYNAMIC;
+		else
+			smps_mode = IEEE80211_SMPS_OFF;
+	}
+
+	/* send SM PS frame to AP */
+	err = ieee80211_send_smps_action(sdata, smps_mode,
+					 ap, ap);
+	if (err)
+		sdata->u.mgd.req_smps = old_req;
+
+	return err;
+}
+
 static int ieee80211_set_power_mgmt(struct wiphy *wiphy, struct net_device *dev,
 				    bool enabled, int timeout)
 {
@@ -1335,6 +1379,11 @@
 	sdata->u.mgd.powersave = enabled;
 	conf->dynamic_ps_timeout = timeout;
 
+	/* no change, but if automatic follow powersave */
+	mutex_lock(&sdata->u.mgd.mtx);
+	__ieee80211_request_smps(sdata, sdata->u.mgd.req_smps);
+	mutex_unlock(&sdata->u.mgd.mtx);
+
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)
 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 
diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index 5d9c797..3559835 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -41,6 +41,30 @@
 	return ret;
 }
 
+static ssize_t ieee80211_if_write(
+	struct ieee80211_sub_if_data *sdata,
+	const char __user *userbuf,
+	size_t count, loff_t *ppos,
+	ssize_t (*write)(struct ieee80211_sub_if_data *, const char *, int))
+{
+	u8 *buf;
+	ssize_t ret = -ENODEV;
+
+	buf = kzalloc(count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	if (copy_from_user(buf, userbuf, count))
+		return -EFAULT;
+
+	rtnl_lock();
+	if (sdata->dev->reg_state == NETREG_REGISTERED)
+		ret = (*write)(sdata, buf, count);
+	rtnl_unlock();
+
+	return ret;
+}
+
 #define IEEE80211_IF_FMT(name, field, format_string)			\
 static ssize_t ieee80211_if_fmt_##name(					\
 	const struct ieee80211_sub_if_data *sdata, char *buf,		\
@@ -71,7 +95,7 @@
 	return scnprintf(buf, buflen, "%pM\n", sdata->field);		\
 }
 
-#define __IEEE80211_IF_FILE(name)					\
+#define __IEEE80211_IF_FILE(name, _write)				\
 static ssize_t ieee80211_if_read_##name(struct file *file,		\
 					char __user *userbuf,		\
 					size_t count, loff_t *ppos)	\
@@ -82,12 +106,24 @@
 }									\
 static const struct file_operations name##_ops = {			\
 	.read = ieee80211_if_read_##name,				\
+	.write = (_write),						\
 	.open = mac80211_open_file_generic,				\
 }
 
+#define __IEEE80211_IF_FILE_W(name)					\
+static ssize_t ieee80211_if_write_##name(struct file *file,		\
+					 const char __user *userbuf,	\
+					 size_t count, loff_t *ppos)	\
+{									\
+	return ieee80211_if_write(file->private_data, userbuf, count,	\
+				  ppos, ieee80211_if_parse_##name);	\
+}									\
+__IEEE80211_IF_FILE(name, ieee80211_if_write_##name)
+
+
 #define IEEE80211_IF_FILE(name, field, format)				\
 		IEEE80211_IF_FMT_##format(name, field)			\
-		__IEEE80211_IF_FILE(name)
+		__IEEE80211_IF_FILE(name, NULL)
 
 /* common attributes */
 IEEE80211_IF_FILE(drop_unencrypted, drop_unencrypted, DEC);
@@ -99,6 +135,70 @@
 IEEE80211_IF_FILE(aid, u.mgd.aid, DEC);
 IEEE80211_IF_FILE(capab, u.mgd.capab, HEX);
 
+static int ieee80211_set_smps(struct ieee80211_sub_if_data *sdata,
+			      enum ieee80211_smps_mode smps_mode)
+{
+	struct ieee80211_local *local = sdata->local;
+	int err;
+
+	if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_STATIC_SMPS) &&
+	    smps_mode == IEEE80211_SMPS_STATIC)
+		return -EINVAL;
+
+	/* auto should be dynamic if in PS mode */
+	if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS) &&
+	    (smps_mode == IEEE80211_SMPS_DYNAMIC ||
+	     smps_mode == IEEE80211_SMPS_AUTOMATIC))
+		return -EINVAL;
+
+	/* supported only on managed interfaces for now */
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&local->iflist_mtx);
+	err = __ieee80211_request_smps(sdata, smps_mode);
+	mutex_unlock(&local->iflist_mtx);
+
+	return err;
+}
+
+static const char *smps_modes[IEEE80211_SMPS_NUM_MODES] = {
+	[IEEE80211_SMPS_AUTOMATIC] = "auto",
+	[IEEE80211_SMPS_OFF] = "off",
+	[IEEE80211_SMPS_STATIC] = "static",
+	[IEEE80211_SMPS_DYNAMIC] = "dynamic",
+};
+
+static ssize_t ieee80211_if_fmt_smps(const struct ieee80211_sub_if_data *sdata,
+				     char *buf, int buflen)
+{
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return -EOPNOTSUPP;
+
+	return snprintf(buf, buflen, "request: %s\nused: %s\n",
+			smps_modes[sdata->u.mgd.req_smps],
+			smps_modes[sdata->u.mgd.ap_smps]);
+}
+
+static ssize_t ieee80211_if_parse_smps(struct ieee80211_sub_if_data *sdata,
+				       const char *buf, int buflen)
+{
+	enum ieee80211_smps_mode mode;
+
+	for (mode = 0; mode < IEEE80211_SMPS_NUM_MODES; mode++) {
+		if (strncmp(buf, smps_modes[mode], buflen) == 0) {
+			int err = ieee80211_set_smps(sdata, mode);
+			if (!err)
+				return buflen;
+			return err;
+		}
+	}
+
+	return -EINVAL;
+}
+
+__IEEE80211_IF_FILE_W(smps);
+
 /* AP attributes */
 IEEE80211_IF_FILE(num_sta_ps, u.ap.num_sta_ps, ATOMIC);
 IEEE80211_IF_FILE(dtim_count, u.ap.dtim_count, DEC);
@@ -109,7 +209,7 @@
 	return scnprintf(buf, buflen, "%u\n",
 			 skb_queue_len(&sdata->u.ap.ps_bc_buf));
 }
-__IEEE80211_IF_FILE(num_buffered_multicast);
+__IEEE80211_IF_FILE(num_buffered_multicast, NULL);
 
 /* WDS attributes */
 IEEE80211_IF_FILE(peer, u.wds.remote_addr, MAC);
@@ -158,6 +258,10 @@
 	debugfs_create_file(#name, 0400, sdata->debugfs.dir, \
 			    sdata, &name##_ops);
 
+#define DEBUGFS_ADD_MODE(name, mode) \
+	debugfs_create_file(#name, mode, sdata->debugfs.dir, \
+			    sdata, &name##_ops);
+
 static void add_sta_files(struct ieee80211_sub_if_data *sdata)
 {
 	DEBUGFS_ADD(drop_unencrypted, sta);
@@ -167,6 +271,7 @@
 	DEBUGFS_ADD(bssid, sta);
 	DEBUGFS_ADD(aid, sta);
 	DEBUGFS_ADD(capab, sta);
+	DEBUGFS_ADD_MODE(smps, 0600);
 }
 
 static void add_ap_files(struct ieee80211_sub_if_data *sdata)
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index ee2d19a..7a849b9 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -140,6 +140,7 @@
 		__field(u8, short_frame_max_tx_count)
 		__field(int, center_freq)
 		__field(int, channel_type)
+		__field(int, smps)
 	),
 
 	TP_fast_assign(
@@ -155,6 +156,7 @@
 		__entry->short_frame_max_tx_count = local->hw.conf.short_frame_max_tx_count;
 		__entry->center_freq = local->hw.conf.channel->center_freq;
 		__entry->channel_type = local->hw.conf.channel_type;
+		__entry->smps = local->hw.conf.smps_mode;
 	),
 
 	TP_printk(
diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index 45ebd06..63b8f86 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -166,3 +166,50 @@
 		spin_unlock_bh(&sta->lock);
 	}
 }
+
+int ieee80211_send_smps_action(struct ieee80211_sub_if_data *sdata,
+			       enum ieee80211_smps_mode smps, const u8 *da,
+			       const u8 *bssid)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct sk_buff *skb;
+	struct ieee80211_mgmt *action_frame;
+
+	/* 27 = header + category + action + smps mode */
+	skb = dev_alloc_skb(27 + local->hw.extra_tx_headroom);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_reserve(skb, local->hw.extra_tx_headroom);
+	action_frame = (void *)skb_put(skb, 27);
+	memcpy(action_frame->da, da, ETH_ALEN);
+	memcpy(action_frame->sa, sdata->dev->dev_addr, ETH_ALEN);
+	memcpy(action_frame->bssid, bssid, ETH_ALEN);
+	action_frame->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
+						  IEEE80211_STYPE_ACTION);
+	action_frame->u.action.category = WLAN_CATEGORY_HT;
+	action_frame->u.action.u.ht_smps.action = WLAN_HT_ACTION_SMPS;
+	switch (smps) {
+	case IEEE80211_SMPS_AUTOMATIC:
+	case IEEE80211_SMPS_NUM_MODES:
+		WARN_ON(1);
+	case IEEE80211_SMPS_OFF:
+		action_frame->u.action.u.ht_smps.smps_control =
+				WLAN_HT_SMPS_CONTROL_DISABLED;
+		break;
+	case IEEE80211_SMPS_STATIC:
+		action_frame->u.action.u.ht_smps.smps_control =
+				WLAN_HT_SMPS_CONTROL_STATIC;
+		break;
+	case IEEE80211_SMPS_DYNAMIC:
+		action_frame->u.action.u.ht_smps.smps_control =
+				WLAN_HT_SMPS_CONTROL_DYNAMIC;
+		break;
+	}
+
+	/* we'll do more on status of this frame */
+	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
+	ieee80211_tx_skb(sdata, skb);
+
+	return 0;
+}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 178e329..e63aecbd 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -297,6 +297,8 @@
 
 	unsigned long timers_running; /* used for quiesce/restart */
 	bool powersave; /* powersave requested for this iface */
+	enum ieee80211_smps_mode req_smps, /* requested smps mode */
+				 ap_smps; /* smps mode AP thinks we're in */
 
 	unsigned long request;
 
@@ -587,6 +589,9 @@
 	/* used for uploading changed mc list */
 	struct work_struct reconfig_filter;
 
+	/* used to reconfigure hardware SM PS */
+	struct work_struct recalc_smps;
+
 	/* aggregated multicast list */
 	struct dev_addr_list *mc_list;
 	int mc_count;
@@ -760,6 +765,8 @@
 	int user_power_level; /* in dBm */
 	int power_constr_level; /* in dBm */
 
+	enum ieee80211_smps_mode smps_mode;
+
 	struct work_struct restart_work;
 
 #ifdef CONFIG_MAC80211_DEBUGFS
@@ -978,6 +985,9 @@
 void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata,
 			  const u8 *da, u16 tid,
 			  u16 initiator, u16 reason_code);
+int ieee80211_send_smps_action(struct ieee80211_sub_if_data *sdata,
+			       enum ieee80211_smps_mode smps, const u8 *da,
+			       const u8 *bssid);
 
 void ieee80211_sta_stop_rx_ba_session(struct ieee80211_sub_if_data *sdata, u8 *da,
 				u16 tid, u16 initiator, u16 reason);
@@ -1088,6 +1098,10 @@
 u32 ieee80211_sta_get_rates(struct ieee80211_local *local,
 			    struct ieee802_11_elems *elems,
 			    enum ieee80211_band band);
+int __ieee80211_request_smps(struct ieee80211_sub_if_data *sdata,
+			     enum ieee80211_smps_mode smps_mode);
+void ieee80211_recalc_smps(struct ieee80211_local *local,
+			   struct ieee80211_sub_if_data *forsdata);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 98320a9..e1293e8 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -113,6 +113,18 @@
 		changed |= IEEE80211_CONF_CHANGE_CHANNEL;
 	}
 
+	if (!conf_is_ht(&local->hw.conf)) {
+		/*
+		 * mac80211.h documents that this is only valid
+		 * when the channel is set to an HT type, and
+		 * that otherwise STATIC is used.
+		 */
+		local->hw.conf.smps_mode = IEEE80211_SMPS_STATIC;
+	} else if (local->hw.conf.smps_mode != local->smps_mode) {
+		local->hw.conf.smps_mode = local->smps_mode;
+		changed |= IEEE80211_CONF_CHANGE_SMPS;
+	}
+
 	if (scan_chan)
 		power = chan->max_power;
 	else
@@ -297,6 +309,16 @@
 }
 EXPORT_SYMBOL(ieee80211_restart_hw);
 
+static void ieee80211_recalc_smps_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local, recalc_smps);
+
+	mutex_lock(&local->iflist_mtx);
+	ieee80211_recalc_smps(local, NULL);
+	mutex_unlock(&local->iflist_mtx);
+}
+
 struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 					const struct ieee80211_ops *ops)
 {
@@ -370,6 +392,8 @@
 	INIT_WORK(&local->restart_work, ieee80211_restart_work);
 
 	INIT_WORK(&local->reconfig_filter, ieee80211_reconfig_filter);
+	INIT_WORK(&local->recalc_smps, ieee80211_recalc_smps_work);
+	local->smps_mode = IEEE80211_SMPS_OFF;
 
 	INIT_WORK(&local->dynamic_ps_enable_work,
 		  ieee80211_dynamic_ps_enable_work);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index cd5dcc3..0a762a9 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -398,6 +398,8 @@
 		__le16 tmp;
 		u32 flags = local->hw.conf.channel->flags;
 
+		/* determine capability flags */
+
 		switch (ht_info->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
 		case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
 			if (flags & IEEE80211_CHAN_NO_HT40PLUS) {
@@ -413,17 +415,64 @@
 			break;
 		}
 
-		tmp = cpu_to_le16(cap);
-		pos = skb_put(skb, sizeof(struct ieee80211_ht_cap)+2);
+		/* set SM PS mode properly */
+		cap &= ~IEEE80211_HT_CAP_SM_PS;
+		/* new association always uses requested smps mode */
+		if (ifmgd->req_smps == IEEE80211_SMPS_AUTOMATIC) {
+			if (ifmgd->powersave)
+				ifmgd->ap_smps = IEEE80211_SMPS_DYNAMIC;
+			else
+				ifmgd->ap_smps = IEEE80211_SMPS_OFF;
+		} else
+			ifmgd->ap_smps = ifmgd->req_smps;
+
+		switch (ifmgd->ap_smps) {
+		case IEEE80211_SMPS_AUTOMATIC:
+		case IEEE80211_SMPS_NUM_MODES:
+			WARN_ON(1);
+		case IEEE80211_SMPS_OFF:
+			cap |= WLAN_HT_CAP_SM_PS_DISABLED <<
+				IEEE80211_HT_CAP_SM_PS_SHIFT;
+			break;
+		case IEEE80211_SMPS_STATIC:
+			cap |= WLAN_HT_CAP_SM_PS_STATIC <<
+				IEEE80211_HT_CAP_SM_PS_SHIFT;
+			break;
+		case IEEE80211_SMPS_DYNAMIC:
+			cap |= WLAN_HT_CAP_SM_PS_DYNAMIC <<
+				IEEE80211_HT_CAP_SM_PS_SHIFT;
+			break;
+		}
+
+		/* reserve and fill IE */
+
+		pos = skb_put(skb, sizeof(struct ieee80211_ht_cap) + 2);
 		*pos++ = WLAN_EID_HT_CAPABILITY;
 		*pos++ = sizeof(struct ieee80211_ht_cap);
 		memset(pos, 0, sizeof(struct ieee80211_ht_cap));
+
+		/* capability flags */
+		tmp = cpu_to_le16(cap);
 		memcpy(pos, &tmp, sizeof(u16));
 		pos += sizeof(u16);
-		/* TODO: needs a define here for << 2 */
+
+		/* AMPDU parameters */
 		*pos++ = sband->ht_cap.ampdu_factor |
-			 (sband->ht_cap.ampdu_density << 2);
+			 (sband->ht_cap.ampdu_density <<
+				IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT);
+
+		/* MCS set */
 		memcpy(pos, &sband->ht_cap.mcs, sizeof(sband->ht_cap.mcs));
+		pos += sizeof(sband->ht_cap.mcs);
+
+		/* extended capabilities */
+		pos += sizeof(__le16);
+
+		/* BF capabilities */
+		pos += sizeof(__le32);
+
+		/* antenna selection */
+		pos += sizeof(u8);
 	}
 
 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
@@ -932,6 +981,7 @@
 
 	mutex_lock(&local->iflist_mtx);
 	ieee80211_recalc_ps(local, -1);
+	ieee80211_recalc_smps(local, sdata);
 	mutex_unlock(&local->iflist_mtx);
 
 	netif_start_queue(sdata->dev);
@@ -2327,6 +2377,11 @@
 		ifmgd->flags |= IEEE80211_STA_WMM_ENABLED;
 
 	mutex_init(&ifmgd->mtx);
+
+	if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS)
+		ifmgd->req_smps = IEEE80211_SMPS_AUTOMATIC;
+	else
+		ifmgd->req_smps = IEEE80211_SMPS_OFF;
 }
 
 /* scan finished notification */
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index b4608f1..0c0850d 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -134,6 +134,40 @@
 	dev_kfree_skb(skb);
 }
 
+static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
+{
+	struct ieee80211_mgmt *mgmt = (void *) skb->data;
+	struct ieee80211_local *local = sta->local;
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+
+	if (ieee80211_is_action(mgmt->frame_control) &&
+	    sdata->vif.type == NL80211_IFTYPE_STATION &&
+	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
+	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
+		/*
+		 * This update looks racy, but isn't -- if we come
+		 * here we've definitely got a station that we're
+		 * talking to, and on a managed interface that can
+		 * only be the AP. And the only other place updating
+		 * this variable is before we're associated.
+		 */
+		switch (mgmt->u.action.u.ht_smps.smps_control) {
+		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
+			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
+			break;
+		case WLAN_HT_SMPS_CONTROL_STATIC:
+			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
+			break;
+		case WLAN_HT_SMPS_CONTROL_DISABLED:
+		default: /* shouldn't happen since we don't send that */
+			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
+			break;
+		}
+
+		ieee80211_queue_work(&local->hw, &local->recalc_smps);
+	}
+}
+
 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct sk_buff *skb2;
@@ -210,6 +244,10 @@
 		rate_control_tx_status(local, sband, sta, skb);
 		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 			ieee80211s_update_metric(local, sta, skb);
+
+		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) &&
+		    (info->flags & IEEE80211_TX_STAT_ACK))
+			ieee80211_frame_acked(sta, skb);
 	}
 
 	rcu_read_unlock();
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index d54dbe8..086ef62 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1170,3 +1170,77 @@
 	return 0;
 }
 
+static int check_mgd_smps(struct ieee80211_if_managed *ifmgd,
+			  enum ieee80211_smps_mode *smps_mode)
+{
+	if (ifmgd->associated) {
+		*smps_mode = ifmgd->ap_smps;
+
+		if (*smps_mode == IEEE80211_SMPS_AUTOMATIC) {
+			if (ifmgd->powersave)
+				*smps_mode = IEEE80211_SMPS_DYNAMIC;
+			else
+				*smps_mode = IEEE80211_SMPS_OFF;
+		}
+
+		return 1;
+	}
+
+	return 0;
+}
+
+/* must hold iflist_mtx */
+void ieee80211_recalc_smps(struct ieee80211_local *local,
+			   struct ieee80211_sub_if_data *forsdata)
+{
+	struct ieee80211_sub_if_data *sdata;
+	enum ieee80211_smps_mode smps_mode = IEEE80211_SMPS_OFF;
+	int count = 0;
+
+	if (forsdata)
+		WARN_ON(!mutex_is_locked(&forsdata->u.mgd.mtx));
+
+	WARN_ON(!mutex_is_locked(&local->iflist_mtx));
+
+	/*
+	 * This function could be improved to handle multiple
+	 * interfaces better, but right now it makes any
+	 * non-station interfaces force SM PS to be turned
+	 * off. If there are multiple station interfaces it
+	 * could also use the best possible mode, e.g. if
+	 * one is in static and the other in dynamic then
+	 * dynamic is ok.
+	 */
+
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!netif_running(sdata->dev))
+			continue;
+		if (sdata->vif.type != NL80211_IFTYPE_STATION)
+			goto set;
+		if (sdata != forsdata) {
+			/*
+			 * This nested is ok -- we are holding the iflist_mtx
+			 * so can't get here twice or so. But it's required
+			 * since normally we acquire it first and then the
+			 * iflist_mtx.
+			 */
+			mutex_lock_nested(&sdata->u.mgd.mtx, SINGLE_DEPTH_NESTING);
+			count += check_mgd_smps(&sdata->u.mgd, &smps_mode);
+			mutex_unlock(&sdata->u.mgd.mtx);
+		} else
+			count += check_mgd_smps(&sdata->u.mgd, &smps_mode);
+
+		if (count > 1) {
+			smps_mode = IEEE80211_SMPS_OFF;
+			break;
+		}
+	}
+
+	if (smps_mode == local->smps_mode)
+		return;
+
+ set:
+	local->smps_mode = smps_mode;
+	/* changed flag is auto-detected for this */
+	ieee80211_hw_config(local, 0);
+}