Some APs seem to drift away from the expected TBTT (timestamp %
beacon_int_in_usec differs quite a bit from zero) which can result in
us waking up way too early to receive a Beacon frame. In order to work
around this, re-configure the Beacon timers after having received a
Beacon frame from the AP (i.e., when we know the offset between the
expected TBTT and the actual time the AP is sending out the Beacon
frame).
Signed-off-by: Jouni Malinen <jouni.malinen@xxxxxxxxxxx>
---
drivers/net/wireless/ath/ath9k/ath9k.h | 1 +
drivers/net/wireless/ath/ath9k/main.c | 9 ++++++++-
drivers/net/wireless/ath/ath9k/recv.c | 7 +++++++
3 files changed, 16 insertions(+), 1 deletion(-)
--- wireless-testing.orig/drivers/net/wireless/ath/ath9k/ath9k.h 2009-05-20 21:21:51.000000000 +0300
+++ wireless-testing/drivers/net/wireless/ath/ath9k/ath9k.h 2009-05-20 21:26:21.000000000 +0300
@@ -522,6 +522,7 @@ struct ath_rfkill {
#define SC_OP_WAIT_FOR_CAB BIT(16)
#define SC_OP_WAIT_FOR_PSPOLL_DATA BIT(17)
#define SC_OP_WAIT_FOR_TX_ACK BIT(18)
+#define SC_OP_BEACON_SYNC BIT(19)
struct ath_bus_ops {
void (*read_cachesize)(struct ath_softc *sc, int *csz);
--- wireless-testing.orig/drivers/net/wireless/ath/ath9k/main.c 2009-05-20 21:25:28.000000000 +0300
+++ wireless-testing/drivers/net/wireless/ath/ath9k/main.c 2009-05-20 21:26:21.000000000 +0300
@@ -487,7 +487,7 @@ static void ath9k_tasklet(unsigned long
* the next Beacon.
*/
DPRINTF(sc, ATH_DBG_PS, "TSFOOR - Sync with next Beacon\n");
- sc->sc_flags |= SC_OP_WAIT_FOR_BEACON;
+ sc->sc_flags |= SC_OP_WAIT_FOR_BEACON | SC_OP_BEACON_SYNC;
}
/* re-enable hardware interrupt */
@@ -914,6 +914,13 @@ static void ath9k_bss_assoc_info(struct
if (avp->av_opmode == NL80211_IFTYPE_STATION) {
sc->curaid = bss_conf->aid;
ath9k_hw_write_associd(sc);
+
+ /*
+ * Request a re-configuration of Beacon related timers
+ * on the receipt of the first Beacon frame (i.e.,
+ * after time sync with the AP).
+ */
+ sc->sc_flags |= SC_OP_BEACON_SYNC;
}
/* Configure the beacon */
--- wireless-testing.orig/drivers/net/wireless/ath/ath9k/recv.c 2009-05-20 21:21:51.000000000 +0300
+++ wireless-testing/drivers/net/wireless/ath/ath9k/recv.c 2009-05-20 21:26:21.000000000 +0300
@@ -521,6 +521,13 @@ static void ath_rx_ps_beacon(struct ath_
if (memcmp(sc->curbssid, mgmt->bssid, ETH_ALEN) != 0)
return; /* not from our current AP */
+ if (sc->sc_flags & SC_OP_BEACON_SYNC) {
+ sc->sc_flags &= ~SC_OP_BEACON_SYNC;
+ DPRINTF(sc, ATH_DBG_PS, "Reconfigure Beacon timers based on "
+ "timestamp from the AP\n");
+ ath_beacon_config(sc, NULL);
+ }
+
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 "
--
Jouni Malinen PGP id EFC895FA
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
