ath9k: add a better fix for beacon timer reliability

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@28211 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/mac80211/patches/585-ath9k_fix_beacon_timer.patch

@@ -1,11 +1,10 @@
 --- a/drivers/net/wireless/ath/ath9k/beacon.c
 +++ b/drivers/net/wireless/ath/ath9k/beacon.c
-@@ -505,7 +505,7 @@ static void ath_beacon_config_ap(struct 
- 	/* NB: the beacon interval is kept internally in TU's */
- 	intval = TU_TO_USEC(conf->beacon_interval);
- 	intval /= ATH_BCBUF;    /* for staggered beacons */
--	nexttbtt = intval;
-+	nexttbtt = roundup(ath9k_hw_gettsf32(ah) + TU_TO_USEC(FUDGE), intval);
+@@ -517,6 +517,7 @@ static void ath_beacon_config_ap(struct 
+ 	/* Set the computed AP beacon timers */
  
- 	/*
- 	 * In AP mode we enable the beacon timers and SWBA interrupts to
+ 	ath9k_hw_disable_interrupts(ah);
++	sc->sc_flags |= SC_OP_TSF_RESET;
+ 	ath9k_beacon_init(sc, nexttbtt, intval);
+ 	sc->beacon.bmisscnt = 0;
+ 	ath9k_hw_set_interrupts(ah, ah->imask);