add delays in pcu.c and qcu.c of ath5k when creating mesh-network on routerstation pro with ar71xx board and atheros 5213A

Hello,
I'm trying to create mesh-network on routerstation pro with ar71xx and atheros 5213A,using openwrt backfire and ath5k. After "iw dev wlan0 interface add mesh type mp mesh_id mymesh","ifconfig mesh up" paralyse the all network orders, I can see "ifconfig" "iwconfig" are dead with "ps",and I cannot kill them. I look up errors in "dmesg", It says the last functions is ath5k_hw_init_beacon() .I add some mdelay(1) between "ath5k_hw_reg_write(ah, 0, AR5K_TIMER0);" and "ath5k_hw_reg_write(ah, next_beacon, AR5K_TIMER0);", "ath5k_hw_reg_write(ah, timer3, AR5K_TIMER3);" and "if (interval & AR5K_BEACON_RESET_TSF)","ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_PISR);" and "AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1,
AR5K_STA_ID1_PWR_SV);" in it tentatively and compile it againthen tried
again, and then add "mdelay(10);" between "AR5K_QUEUE_DFS_LOCAL_IFS(queue));" and "AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),AR5K_QCU_MISC_DCU_EARLY);" in "ath5k_hw_reset_tx_queue()" in qcu.c .Finally the mesh-network is OK! I'm not sure what is exactly wrong with ath5k,is this a bug? or did I do something wrong? Here is the patch I used:

diff -ruN a/config.mk b/config.mk

config.mk +3 -0

@@ -1,5 +1,8 @@
 export
 
+# add by zheng
+# CONFIG_ATH5K_DEBUG=y
+
 ## NOTE
 ## Make sure to have each variable declaration start
 ## in the first column, no whitespace allowed.

diff -ruN a/drivers/net/wireless/ath/ath5k/pcu.c
b/drivers/net/wireless/ath/ath5k/pcu.c ---
a/drivers/net/wireless/ath/ath5k/pcu.c 2010-03-26 18:25:50.000000000

+++ b/drivers/net/wireless/ath/ath5k/pcu.c 2010-09-29 21:21:03.915143556
+0000 @@ -25,6 +25,7 @@
\*********************************/

#include <asm/unaligned.h>

config.mk +7 -0

+#include <linux/delay.h>
 
 #include "ath5k.h"
 #include "reg.h"

@@ -618,11 +619,15 @@
 	    ah->ah_sc->opmode == NL80211_IFTYPE_MESH_POINT)
 		ath5k_hw_reg_write(ah, 0, AR5K_TIMER0);
 
+	mdelay(1);
+
 	ath5k_hw_reg_write(ah, next_beacon, AR5K_TIMER0);
 	ath5k_hw_reg_write(ah, timer1, AR5K_TIMER1);
 	ath5k_hw_reg_write(ah, timer2, AR5K_TIMER2);
 	ath5k_hw_reg_write(ah, timer3, AR5K_TIMER3);
 
+	mdelay(1);
+
 	/* Force a TSF reset if requested and enable beacons */
 	if (interval & AR5K_BEACON_RESET_TSF)
 		ath5k_hw_reset_tsf(ah);

@@ -641,6 +646,8 @@
 	else
 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_PISR);
 
+	mdelay(1);
+
 	/* TODO: Set enchanced sleep registers on AR5212
 	 * based on vif->bss_conf params, until then
 	 * disable power save reporting.*/

diff -ruN a/drivers/net/wireless/ath/ath5k/qcu.c
b/drivers/net/wireless/ath/ath5k/qcu.c ---
a/drivers/net/wireless/ath/ath5k/qcu.c 2010-03-26 18:25:50.000000000

+++ b/drivers/net/wireless/ath/ath5k/qcu.c 2010-09-29 21:19:04.863143555
+0000 @@ -24,6 +24,7 @@
#include "reg.h"
#include "debug.h"
#include "base.h"

config.mk +1 -0

+#include <linux/delay.h> /* add by zheng */
 
 /*
  * Get properties for a transmit queue