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Commit cc65965c authored by Jouni Malinen's avatar Jouni Malinen Committed by John W. Linville
Browse files

ath9k: Fix PS mode operation to receive buffered broadcast/multicast frames 



The previous implementation was moving back to NETWORK SLEEP state
immediately after receiving a Beacon frame. This means that we are
unlikely to receive all the buffered broadcast/multicast frames that
would be sent after DTIM Beacon frames. Fix this by parsing the Beacon
frame and remaining awake, if needed, to receive the buffered
broadcast/multicast frames. The last buffered frame will trigger the
move back into NETWORK SLEEP state.

If the last broadcast/multicast frame is not received properly (or if
the AP fails to send it), the next Beacon frame will work as a backup
trigger for returning into NETWORK SLEEP.

A new debug type, PS (debug=0x800 module parameter), is added to make
it easier to debug potential power save issues in the
future. Currently, this is only used for the Beacon frame and buffered
broadcast/multicast receiving.

Signed-off-by: default avatarJouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 9d64a3cf

drivers/net/wireless/ath/ath9k/ath9k.h

+1 −0
Original line number Diff line number Diff line
@@ -515,6 +515,7 @@ struct ath_rfkill { 
#define SC_OP_LED_ON            BIT(13)

#define SC_OP_SCANNING          BIT(14)

#define SC_OP_TSF_RESET         BIT(15)

#define SC_OP_WAIT_FOR_CAB      BIT(16)



struct ath_bus_ops {

	void		(*read_cachesize)(struct ath_softc *sc, int *csz);

drivers/net/wireless/ath/ath9k/debug.h

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ enum ATH_DEBUG { 
	ATH_DBG_BEACON		= 0x00000100,

	ATH_DBG_CONFIG		= 0x00000200,

	ATH_DBG_FATAL		= 0x00000400,

	ATH_DBG_PS		= 0x00000800,

	ATH_DBG_ANY		= 0xffffffff

};

drivers/net/wireless/ath/ath9k/recv.c

+112 −7
Original line number Diff line number Diff line
@@ -473,6 +473,112 @@ void ath_flushrecv(struct ath_softc *sc) 
	spin_unlock_bh(&sc->rx.rxflushlock);

}



static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)

{

	/* Check whether the Beacon frame has DTIM indicating buffered bc/mc */

	struct ieee80211_mgmt *mgmt;

	u8 *pos, *end, id, elen;

	struct ieee80211_tim_ie *tim;



	mgmt = (struct ieee80211_mgmt *)skb->data;

	pos = mgmt->u.beacon.variable;

	end = skb->data + skb->len;



	while (pos + 2 < end) {

		id = *pos++;

		elen = *pos++;

		if (pos + elen > end)

			break;



		if (id == WLAN_EID_TIM) {

			if (elen < sizeof(*tim))

				break;

			tim = (struct ieee80211_tim_ie *) pos;

			if (tim->dtim_count != 0)

				break;

			return tim->bitmap_ctrl & 0x01;

		}



		pos += elen;

	}



	return false;

}



static void ath_rx_ps_back_to_sleep(struct ath_softc *sc)

{

	sc->sc_flags &= ~(SC_OP_WAIT_FOR_BEACON | SC_OP_WAIT_FOR_CAB);

	if (sc->hw->conf.flags & IEEE80211_CONF_PS)

		ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);

}



static void ath_rx_ps_beacon(struct ath_softc *sc, struct sk_buff *skb)

{

	struct ieee80211_mgmt *mgmt;



	if (skb->len < 24 + 8 + 2 + 2)

		return;



	mgmt = (struct ieee80211_mgmt *)skb->data;

	if (memcmp(sc->curbssid, mgmt->bssid, ETH_ALEN) != 0)

		return; /* not from our current AP */



	if (!(sc->hw->conf.flags & IEEE80211_CONF_PS)) {

		/* We are not in PS mode anymore; remain awake */

		DPRINTF(sc, ATH_DBG_PS, "Not in PS mode anymore, remain "

			"awake\n");

		sc->sc_flags &= ~(SC_OP_WAIT_FOR_BEACON | SC_OP_WAIT_FOR_CAB);

		return;

	}



	if (ath_beacon_dtim_pending_cab(skb)) {

		/*

		 * Remain awake waiting for buffered broadcast/multicast

		 * frames.

		 */

		DPRINTF(sc, ATH_DBG_PS, "Received DTIM beacon indicating "

			"buffered broadcast/multicast frame(s)\n");

		sc->sc_flags |= SC_OP_WAIT_FOR_CAB;

		return;

	}



	if (sc->sc_flags & SC_OP_WAIT_FOR_CAB) {

		/*

		 * This can happen if a broadcast frame is dropped or the AP

		 * fails to send a frame indicating that all CAB frames have

		 * been delivered.

		 */

		DPRINTF(sc, ATH_DBG_PS, "PS wait for CAB frames timed out\n");

	}



	/* No more broadcast/multicast frames to be received at this point. */

	ath_rx_ps_back_to_sleep(sc);

}



static void ath_rx_ps(struct ath_softc *sc, struct sk_buff *skb)

{

	struct ieee80211_hdr *hdr;



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



	/* Process Beacon and CAB receive in PS state */

	if (ieee80211_is_beacon(hdr->frame_control))

		ath_rx_ps_beacon(sc, skb);

	else if ((sc->sc_flags & SC_OP_WAIT_FOR_CAB) &&

		 (ieee80211_is_data(hdr->frame_control) ||

		  ieee80211_is_action(hdr->frame_control)) &&

		 is_multicast_ether_addr(hdr->addr1) &&

		 !ieee80211_has_moredata(hdr->frame_control)) {

		DPRINTF(sc, ATH_DBG_PS, "All PS CAB frames received, back to "

			"sleep\n");

		/*

		 * No more broadcast/multicast frames to be received at this

		 * point.

		 */

		ath_rx_ps_back_to_sleep(sc);

	}

}



static void ath_rx_send_to_mac80211(struct ath_softc *sc, struct sk_buff *skb,

				    struct ieee80211_rx_status *rx_status)

{
@@ -667,8 +773,6 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush) 
			rx_status.flag &= ~RX_FLAG_DECRYPTED;

		}



		ath_rx_send_to_mac80211(sc, skb, &rx_status);



		/* We will now give hardware our shiny new allocated skb */

		bf->bf_mpdu = requeue_skb;

		bf->bf_buf_addr = dma_map_single(sc->dev, requeue_skb->data,
@@ -680,6 +784,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush) 
			bf->bf_mpdu = NULL;

			DPRINTF(sc, ATH_DBG_FATAL,

				"dma_mapping_error() on RX\n");

			ath_rx_send_to_mac80211(sc, skb, &rx_status);

			break;

		}

		bf->bf_dmacontext = bf->bf_buf_addr;
@@ -695,11 +800,11 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush) 
			sc->rx.rxotherant = 0;

		}



		if (ieee80211_is_beacon(fc) &&

				(sc->sc_flags & SC_OP_WAIT_FOR_BEACON)) {

			sc->sc_flags &= ~SC_OP_WAIT_FOR_BEACON;

			ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_NETWORK_SLEEP);

		}

		if (unlikely(sc->sc_flags & SC_OP_WAIT_FOR_BEACON))

			ath_rx_ps(sc, skb);



		ath_rx_send_to_mac80211(sc, skb, &rx_status);



requeue:

		list_move_tail(&bf->list, &sc->rx.rxbuf);

		ath_rx_buf_link(sc, bf);