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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
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+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,
+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);
			}
		}
	}

+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)