mac80211: implement dynamic power save

This patch implements dynamic power save for mac80211. Basically it means enabling power save mode after an idle period. Implementing it dynamically gives a good compromise of low power consumption and low latency. Some hardware have support for this in firmware, but some require the host to do it. The dynamic power save is implemented by adding an timeout to ieee80211_subif_start_xmit(). The timeout can be enabled from userspace with Wireless Extensions. For example, the command below enables the dynamic power save and sets the time timeout to 500 ms: iwconfig wlan0 power timeout 500m Power save now only works with devices which handle power save in firmware. It's also disabled by default and the heuristics when and how to enable is considered as a policy decision and will be left for the userspace to handle. In case the firmware has support for this, drivers can disable this feature with IEEE80211_HW_NO_STACK_DYNAMIC_PS. Big thanks to Johannes Berg for the help with the design and code. Signed-off-by: Kalle Valo <kalle.valo@nokia.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>

mac80211: implement dynamic power save
This patch implements dynamic power save for mac80211. Basically it means enabling power save mode after an idle period. Implementing it dynamically gives a good compromise of low power consumption and low latency. Some hardware have support for this in firmware, but some require the host to do it. The dynamic power save is implemented by adding an timeout to ieee80211_subif_start_xmit(). The timeout can be enabled from userspace with Wireless Extensions. For example, the command below enables the dynamic power save and sets the time timeout to 500 ms: iwconfig wlan0 power timeout 500m Power save now only works with devices which handle power save in firmware. It's also disabled by default and the heuristics when and how to enable is considered as a policy decision and will be left for the userspace to handle. In case the firmware has support for this, drivers can disable this feature with IEEE80211_HW_NO_STACK_DYNAMIC_PS. Big thanks to Johannes Berg for the help with the design and code. Signed-off-by: Kalle Valo <kalle.valo@nokia.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Kalle Valo · John W. Linville
1 parent ce7c9111a9
Showing 6 changed files with 103 additions and 12 deletions Side-by-side Diff
include/net/mac80211.h
net/mac80211/ieee80211_i.h
net/mac80211/main.c
net/mac80211/mlme.c
net/mac80211/tx.c
net/mac80211/wext.c
@@ -854,6 +854,11 @@
  *
  * @IEEE80211_HW_AMPDU_AGGREGATION:
  *	Hardware supports 11n A-MPDU aggregation.
+ *
+ * @IEEE80211_HW_NO_STACK_DYNAMIC_PS:
+ *	Hardware which has dynamic power save support, meaning
+ *	that power save is enabled in idle periods, and don't need support
+ *	from stack.
  */
 enum ieee80211_hw_flags {
 	IEEE80211_HW_RX_INCLUDES_FCS			= 1<<1,
@@ -866,6 +871,7 @@
 	IEEE80211_HW_NOISE_DBM				= 1<<8,
 	IEEE80211_HW_SPECTRUM_MGMT			= 1<<9,
 	IEEE80211_HW_AMPDU_AGGREGATION			= 1<<10,
+	IEEE80211_HW_NO_STACK_DYNAMIC_PS		= 1<<11,
 };
  
 /**
@@ -540,6 +540,7 @@
  
 enum queue_stop_reason {
 	IEEE80211_QUEUE_STOP_REASON_DRIVER,
+	IEEE80211_QUEUE_STOP_REASON_PS,
 };
  
 /* maximum number of hardware queues we support. */
  
@@ -693,7 +694,12 @@
 				*/
 	int wifi_wme_noack_test;
 	unsigned int wmm_acm; /* bit field of ACM bits (BIT(802.1D tag)) */
+
 	bool powersave;
+	int dynamic_ps_timeout;
+	struct work_struct dynamic_ps_enable_work;
+	struct work_struct dynamic_ps_disable_work;
+	struct timer_list dynamic_ps_timer;
  
 #ifdef CONFIG_MAC80211_DEBUGFS
 	struct local_debugfsdentries {
@@ -976,6 +982,10 @@
 int ieee80211_set_freq(struct ieee80211_sub_if_data *sdata, int freq);
 u64 ieee80211_mandatory_rates(struct ieee80211_local *local,
 			      enum ieee80211_band band);
+
+void ieee80211_dynamic_ps_enable_work(struct work_struct *work);
+void ieee80211_dynamic_ps_disable_work(struct work_struct *work);
+void ieee80211_dynamic_ps_timer(unsigned long data);
  
 void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
 				     enum queue_stop_reason reason);
@@ -729,6 +729,13 @@
  
 	INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);
  
+	INIT_WORK(&local->dynamic_ps_enable_work,
+		  ieee80211_dynamic_ps_enable_work);
+	INIT_WORK(&local->dynamic_ps_disable_work,
+		  ieee80211_dynamic_ps_disable_work);
+	setup_timer(&local->dynamic_ps_timer,
+		    ieee80211_dynamic_ps_timer, (unsigned long) local);
+
 	sta_info_init(local);
  
 	tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
@@ -745,8 +745,14 @@
 	ieee80211_bss_info_change_notify(sdata, bss_info_changed);
  
 	if (local->powersave) {
-		local->hw.conf.flags |= IEEE80211_CONF_PS;
-		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+		if (local->dynamic_ps_timeout > 0)
+			mod_timer(&local->dynamic_ps_timer, jiffies +
+				  msecs_to_jiffies(local->dynamic_ps_timeout));
+		else {
+			conf->flags |= IEEE80211_CONF_PS;
+			ieee80211_hw_config(local,
+					    IEEE80211_CONF_CHANGE_PS);
+		}
 	}
  
 	netif_tx_start_all_queues(sdata->dev);
@@ -866,6 +872,9 @@
 	local->oper_channel_type = NL80211_CHAN_NO_HT;
 	config_changed |= IEEE80211_CONF_CHANGE_HT;
  
+	del_timer_sync(&local->dynamic_ps_timer);
+	cancel_work_sync(&local->dynamic_ps_enable_work);
+
 	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
 		local->hw.conf.flags &= ~IEEE80211_CONF_PS;
 		config_changed |= IEEE80211_CONF_CHANGE_PS;
@@ -2592,5 +2601,41 @@
 	list_for_each_entry_rcu(sdata, &local->interfaces, list)
 		ieee80211_restart_sta_timer(sdata);
 	rcu_read_unlock();
+}
+
+void ieee80211_dynamic_ps_disable_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local,
+			     dynamic_ps_disable_work);
+
+	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
+		local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+	}
+
+	ieee80211_wake_queues_by_reason(&local->hw,
+					IEEE80211_QUEUE_STOP_REASON_PS);
+}
+
+void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local,
+			     dynamic_ps_enable_work);
+
+	if (local->hw.conf.flags & IEEE80211_CONF_PS)
+		return;
+
+	local->hw.conf.flags |= IEEE80211_CONF_PS;
+
+	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+}
+
+void ieee80211_dynamic_ps_timer(unsigned long data)
+{
+	struct ieee80211_local *local = (void *) data;
+
+	queue_work(local->hw.workqueue, &local->dynamic_ps_enable_work);
 }
@@ -1473,6 +1473,19 @@
 		goto fail;
 	}
  
+	if (!(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS) &&
+	    local->dynamic_ps_timeout > 0) {
+		if (local->hw.conf.flags & IEEE80211_CONF_PS) {
+			ieee80211_stop_queues_by_reason(&local->hw,
+							IEEE80211_QUEUE_STOP_REASON_PS);
+			queue_work(local->hw.workqueue,
+				   &local->dynamic_ps_disable_work);
+		}
+
+		mod_timer(&local->dynamic_ps_timer, jiffies +
+			  msecs_to_jiffies(local->dynamic_ps_timeout));
+	}
+
 	nh_pos = skb_network_header(skb) - skb->data;
 	h_pos = skb_transport_header(skb) - skb->data;
  
@@ -833,7 +833,7 @@
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 	struct ieee80211_conf *conf = &local->hw.conf;
-	int ret = 0;
+	int ret = 0, timeout = 0;
 	bool ps;
  
 	if (sdata->vif.type != NL80211_IFTYPE_STATION)
@@ -841,6 +841,7 @@
  
 	if (wrq->disabled) {
 		ps = false;
+		timeout = 0;
 		goto set;
 	}
  
  
  
  
  
@@ -850,22 +851,31 @@
 	case IW_POWER_ALL_R:    /* If explicitely state all */
 		ps = true;
 		break;
-	default:                /* Otherwise we don't support it */
-		return -EINVAL;
+	default:                /* Otherwise we ignore */
+		break;
 	}
  
-	if (ps == local->powersave)
-		return ret;
+	if (wrq->flags & IW_POWER_TIMEOUT)
+		timeout = wrq->value / 1000;
  
 set:
+	if (ps == local->powersave && timeout == local->dynamic_ps_timeout)
+		return ret;
+
 	local->powersave = ps;
+	local->dynamic_ps_timeout = timeout;
  
 	if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
-		if (local->powersave)
-			conf->flags |= IEEE80211_CONF_PS;
-		else
-			conf->flags &= ~IEEE80211_CONF_PS;
-
+		if (!(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS) &&
+		    local->dynamic_ps_timeout > 0)
+			mod_timer(&local->dynamic_ps_timer, jiffies +
+				  msecs_to_jiffies(local->dynamic_ps_timeout));
+		else {
+			if (local->powersave)
+				conf->flags |= IEEE80211_CONF_PS;
+			else
+				conf->flags &= ~IEEE80211_CONF_PS;
+		}
 		ret = ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 	}
...	...	@@ -854,6 +854,11 @@
854	854	*
855	855	* @IEEE80211_HW_AMPDU_AGGREGATION:
856	856	* Hardware supports 11n A-MPDU aggregation.
	857	+ *
	858	+ * @IEEE80211_HW_NO_STACK_DYNAMIC_PS:
	859	+ * Hardware which has dynamic power save support, meaning
	860	+ * that power save is enabled in idle periods, and don't need support
	861	+ * from stack.
857	862	*/
858	863	enum ieee80211_hw_flags {
859	864	IEEE80211_HW_RX_INCLUDES_FCS = 1<<1,
...	...	@@ -866,6 +871,7 @@
866	871	IEEE80211_HW_NOISE_DBM = 1<<8,
867	872	IEEE80211_HW_SPECTRUM_MGMT = 1<<9,
868	873	IEEE80211_HW_AMPDU_AGGREGATION = 1<<10,
	874	+ IEEE80211_HW_NO_STACK_DYNAMIC_PS = 1<<11,
869	875	};
870	876
871	877	/**
...	...	@@ -540,6 +540,7 @@
540	540
541	541	enum queue_stop_reason {
542	542	IEEE80211_QUEUE_STOP_REASON_DRIVER,
	543	+ IEEE80211_QUEUE_STOP_REASON_PS,
543	544	};
544	545
545	546	/* maximum number of hardware queues we support. */
546	547
...	...	@@ -693,7 +694,12 @@
693	694	*/
694	695	int wifi_wme_noack_test;
695	696	unsigned int wmm_acm; /* bit field of ACM bits (BIT(802.1D tag)) */
	697	+
696	698	bool powersave;
	699	+ int dynamic_ps_timeout;
	700	+ struct work_struct dynamic_ps_enable_work;
	701	+ struct work_struct dynamic_ps_disable_work;
	702	+ struct timer_list dynamic_ps_timer;
697	703
698	704	#ifdef CONFIG_MAC80211_DEBUGFS
699	705	struct local_debugfsdentries {
...	...	@@ -976,6 +982,10 @@
976	982	int ieee80211_set_freq(struct ieee80211_sub_if_data *sdata, int freq);
977	983	u64 ieee80211_mandatory_rates(struct ieee80211_local *local,
978	984	enum ieee80211_band band);
	985	+
	986	+void ieee80211_dynamic_ps_enable_work(struct work_struct *work);
	987	+void ieee80211_dynamic_ps_disable_work(struct work_struct *work);
	988	+void ieee80211_dynamic_ps_timer(unsigned long data);
979	989
980	990	void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
981	991	enum queue_stop_reason reason);
...	...	@@ -729,6 +729,13 @@
729	729
730	730	INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);
731	731
	732	+ INIT_WORK(&local->dynamic_ps_enable_work,
	733	+ ieee80211_dynamic_ps_enable_work);
	734	+ INIT_WORK(&local->dynamic_ps_disable_work,
	735	+ ieee80211_dynamic_ps_disable_work);
	736	+ setup_timer(&local->dynamic_ps_timer,
	737	+ ieee80211_dynamic_ps_timer, (unsigned long) local);
	738	+
732	739	sta_info_init(local);
733	740
734	741	tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
...	...	@@ -745,8 +745,14 @@
745	745	ieee80211_bss_info_change_notify(sdata, bss_info_changed);
746	746
747	747	if (local->powersave) {
748		- local->hw.conf.flags \|= IEEE80211_CONF_PS;
749		- ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
	748	+ if (local->dynamic_ps_timeout > 0)
	749	+ mod_timer(&local->dynamic_ps_timer, jiffies +
	750	+ msecs_to_jiffies(local->dynamic_ps_timeout));
	751	+ else {
	752	+ conf->flags \|= IEEE80211_CONF_PS;
	753	+ ieee80211_hw_config(local,
	754	+ IEEE80211_CONF_CHANGE_PS);
	755	+ }
750	756	}
751	757
752	758	netif_tx_start_all_queues(sdata->dev);
...	...	@@ -866,6 +872,9 @@
866	872	local->oper_channel_type = NL80211_CHAN_NO_HT;
867	873	config_changed \|= IEEE80211_CONF_CHANGE_HT;
868	874
	875	+ del_timer_sync(&local->dynamic_ps_timer);
	876	+ cancel_work_sync(&local->dynamic_ps_enable_work);
	877	+
869	878	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
870	879	local->hw.conf.flags &= ~IEEE80211_CONF_PS;
871	880	config_changed \|= IEEE80211_CONF_CHANGE_PS;
...	...	@@ -2592,5 +2601,41 @@
2592	2601	list_for_each_entry_rcu(sdata, &local->interfaces, list)
2593	2602	ieee80211_restart_sta_timer(sdata);
2594	2603	rcu_read_unlock();
	2604	+}
	2605	+
	2606	+void ieee80211_dynamic_ps_disable_work(struct work_struct *work)
	2607	+{
	2608	+ struct ieee80211_local *local =
	2609	+ container_of(work, struct ieee80211_local,
	2610	+ dynamic_ps_disable_work);
	2611	+
	2612	+ if (local->hw.conf.flags & IEEE80211_CONF_PS) {
	2613	+ local->hw.conf.flags &= ~IEEE80211_CONF_PS;
	2614	+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
	2615	+ }
	2616	+
	2617	+ ieee80211_wake_queues_by_reason(&local->hw,
	2618	+ IEEE80211_QUEUE_STOP_REASON_PS);
	2619	+}
	2620	+
	2621	+void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
	2622	+{
	2623	+ struct ieee80211_local *local =
	2624	+ container_of(work, struct ieee80211_local,
	2625	+ dynamic_ps_enable_work);
	2626	+
	2627	+ if (local->hw.conf.flags & IEEE80211_CONF_PS)
	2628	+ return;
	2629	+
	2630	+ local->hw.conf.flags \|= IEEE80211_CONF_PS;
	2631	+
	2632	+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
	2633	+}
	2634	+
	2635	+void ieee80211_dynamic_ps_timer(unsigned long data)
	2636	+{
	2637	+ struct ieee80211_local local = (void ) data;
	2638	+
	2639	+ queue_work(local->hw.workqueue, &local->dynamic_ps_enable_work);
2595	2640	}
...	...	@@ -1473,6 +1473,19 @@
1473	1473	goto fail;
1474	1474	}
1475	1475
	1476	+ if (!(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS) &&
	1477	+ local->dynamic_ps_timeout > 0) {
	1478	+ if (local->hw.conf.flags & IEEE80211_CONF_PS) {
	1479	+ ieee80211_stop_queues_by_reason(&local->hw,
	1480	+ IEEE80211_QUEUE_STOP_REASON_PS);
	1481	+ queue_work(local->hw.workqueue,
	1482	+ &local->dynamic_ps_disable_work);
	1483	+ }
	1484	+
	1485	+ mod_timer(&local->dynamic_ps_timer, jiffies +
	1486	+ msecs_to_jiffies(local->dynamic_ps_timeout));
	1487	+ }
	1488	+
1476	1489	nh_pos = skb_network_header(skb) - skb->data;
1477	1490	h_pos = skb_transport_header(skb) - skb->data;
1478	1491
...	...	@@ -833,7 +833,7 @@
833	833	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
834	834	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
835	835	struct ieee80211_conf *conf = &local->hw.conf;
836		- int ret = 0;
	836	+ int ret = 0, timeout = 0;
837	837	bool ps;
838	838
839	839	if (sdata->vif.type != NL80211_IFTYPE_STATION)
...	...	@@ -841,6 +841,7 @@
841	841
842	842	if (wrq->disabled) {
843	843	ps = false;
	844	+ timeout = 0;
844	845	goto set;
845	846	}
846	847
847	848
848	849
849	850
850	851
...	...	@@ -850,22 +851,31 @@
850	851	case IW_POWER_ALL_R: /* If explicitely state all */
851	852	ps = true;
852	853	break;
853		- default: /* Otherwise we don't support it */
854		- return -EINVAL;
	854	+ default: /* Otherwise we ignore */
	855	+ break;
855	856	}
856	857
857		- if (ps == local->powersave)
858		- return ret;
	858	+ if (wrq->flags & IW_POWER_TIMEOUT)
	859	+ timeout = wrq->value / 1000;
859	860
860	861	set:
	862	+ if (ps == local->powersave && timeout == local->dynamic_ps_timeout)
	863	+ return ret;
	864	+
861	865	local->powersave = ps;
	866	+ local->dynamic_ps_timeout = timeout;
862	867
863	868	if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
864		- if (local->powersave)
865		- conf->flags \|= IEEE80211_CONF_PS;
866		- else
867		- conf->flags &= ~IEEE80211_CONF_PS;
868		-
	869	+ if (!(local->hw.flags & IEEE80211_HW_NO_STACK_DYNAMIC_PS) &&
	870	+ local->dynamic_ps_timeout > 0)
	871	+ mod_timer(&local->dynamic_ps_timer, jiffies +
	872	+ msecs_to_jiffies(local->dynamic_ps_timeout));
	873	+ else {
	874	+ if (local->powersave)
	875	+ conf->flags \|= IEEE80211_CONF_PS;
	876	+ else
	877	+ conf->flags &= ~IEEE80211_CONF_PS;
	878	+ }
869	879	ret = ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
870	880	}
871	881