Commit 572e0012 authored by Kalle Valo's avatar Kalle Valo Committed by John W. Linville
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mac80211: use ps-poll when dynamic power save mode is disabled 



When a directed tim bit is set, mac80211 currently disables power save
ands sends a null frame to the AP. But if dynamic power save is
disabled, mac80211 will not enable power save ever gain. Fix this by
adding ps-poll functionality to mac80211. When a directed tim bit is
set, mac80211 sends a ps-poll frame to the AP and checks for the more
data bit in the returned data frames.

Using ps-poll is slower than waking up with null frame, but it's saves more
power in cases where the traffic is low. Userspace can control if either
ps-poll or null wakeup method is used by enabling and disabling dynamic
power save.

Signed-off-by: default avatarKalle Valo <kalle.valo@nokia.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 1fb3606b

net/mac80211/ieee80211_i.h

+3 −0
Original line number Diff line number Diff line
@@ -728,6 +728,7 @@ struct ieee80211_local { 
	unsigned int wmm_acm; /* bit field of ACM bits (BIT(802.1D tag)) */



	bool powersave;

	bool pspolling;

	struct work_struct dynamic_ps_enable_work;

	struct work_struct dynamic_ps_disable_work;

	struct timer_list dynamic_ps_timer;
@@ -921,6 +922,8 @@ u32 ieee80211_sta_get_rates(struct ieee80211_local *local, 
			    enum ieee80211_band band);

void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,

			      u8 *ssid, size_t ssid_len);

void ieee80211_send_pspoll(struct ieee80211_local *local,

			   struct ieee80211_sub_if_data *sdata);



/* scan/BSS handling */

int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,

net/mac80211/mlme.c

+51 −3
Original line number Diff line number Diff line
@@ -511,6 +511,39 @@ static void ieee80211_send_deauth_disassoc(struct ieee80211_sub_if_data *sdata, 
	ieee80211_tx_skb(sdata, skb, ifsta->flags & IEEE80211_STA_MFP_ENABLED);

}



void ieee80211_send_pspoll(struct ieee80211_local *local,

			   struct ieee80211_sub_if_data *sdata)

{

	struct ieee80211_if_sta *ifsta = &sdata->u.sta;

	struct ieee80211_pspoll *pspoll;

	struct sk_buff *skb;

	u16 fc;



	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*pspoll));

	if (!skb) {

		printk(KERN_DEBUG "%s: failed to allocate buffer for "

		       "pspoll frame\n", sdata->dev->name);

		return;

	}

	skb_reserve(skb, local->hw.extra_tx_headroom);



	pspoll = (struct ieee80211_pspoll *) skb_put(skb, sizeof(*pspoll));

	memset(pspoll, 0, sizeof(*pspoll));

	fc = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_PSPOLL | IEEE80211_FCTL_PM;

	pspoll->frame_control = cpu_to_le16(fc);

	pspoll->aid = cpu_to_le16(ifsta->aid);



	/* aid in PS-Poll has its two MSBs each set to 1 */

	pspoll->aid |= cpu_to_le16(1 << 15 | 1 << 14);



	memcpy(pspoll->bssid, ifsta->bssid, ETH_ALEN);

	memcpy(pspoll->ta, sdata->dev->dev_addr, ETH_ALEN);



	ieee80211_tx_skb(sdata, skb, 0);



	return;

}



/* MLME */

static void ieee80211_sta_def_wmm_params(struct ieee80211_sub_if_data *sdata,

					 struct ieee80211_bss *bss)
@@ -1868,9 +1901,24 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata, 
		directed_tim = ieee80211_check_tim(&elems, ifsta->aid);



		if (directed_tim) {

			if (local->hw.conf.dynamic_ps_timeout > 0) {

				local->hw.conf.flags &= ~IEEE80211_CONF_PS;

			ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);

				ieee80211_hw_config(local,

						    IEEE80211_CONF_CHANGE_PS);

				ieee80211_send_nullfunc(local, sdata, 0);

			} else {

				local->pspolling = true;



				/*

				 * Here is assumed that the driver will be

				 * able to send ps-poll frame and receive a

				 * response even though power save mode is

				 * enabled, but some drivers might require

				 * to disable power save here. This needs

				 * to be investigated.

				 */

				ieee80211_send_pspoll(local, sdata);

			}

		}

	}

net/mac80211/rx.c

+34 −0
Original line number Diff line number Diff line
@@ -731,6 +731,39 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) 
	return result;

}



static ieee80211_rx_result debug_noinline

ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)

{

	struct ieee80211_local *local;

	struct ieee80211_hdr *hdr;

	struct sk_buff *skb;



	local = rx->local;

	skb = rx->skb;

	hdr = (struct ieee80211_hdr *) skb->data;



	if (!local->pspolling)

		return RX_CONTINUE;



	if (!ieee80211_has_fromds(hdr->frame_control))

		/* this is not from AP */

		return RX_CONTINUE;



	if (!ieee80211_is_data(hdr->frame_control))

		return RX_CONTINUE;



	if (!ieee80211_has_moredata(hdr->frame_control)) {

		/* AP has no more frames buffered for us */

		local->pspolling = false;

		return RX_CONTINUE;

	}



	/* more data bit is set, let's request a new frame from the AP */

	ieee80211_send_pspoll(local, rx->sdata);



	return RX_CONTINUE;

}



static void ap_sta_ps_start(struct sta_info *sta)

{

	struct ieee80211_sub_if_data *sdata = sta->sdata;
@@ -1987,6 +2020,7 @@ static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata, 
	CALL_RXH(ieee80211_rx_h_passive_scan)

	CALL_RXH(ieee80211_rx_h_check)

	CALL_RXH(ieee80211_rx_h_decrypt)

	CALL_RXH(ieee80211_rx_h_check_more_data)

	CALL_RXH(ieee80211_rx_h_sta_process)

	CALL_RXH(ieee80211_rx_h_defragment)

	CALL_RXH(ieee80211_rx_h_ps_poll)

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