ath9k: Update Beacon timers based on timestamp from the AP

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@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 5759c9465029..61da08a1648c 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -487,7 +487,7 @@ static void ath9k_tasklet(unsigned long data)
                  * 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 ath_softc *sc,
                 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 */