Freebsd9.0 TDMA: stuck beacon problem

[saint]

Hi Adrian:
    This is Michael. 
    I'm trying to implement TDMA connection with two Atheros cards(AR5416 and AR9285) working on freebsd 9.0-release.
    After reading the handbook, I added the build option IEEE80211_SUPPORT_TDMA, and modified loader.conf as:
if_ath_load="YES"
if_ath_pci_load="YES"
    I rebuilt and reinstalled the kernel, reboot ...
    After that, the ath driver can be loaded and I could configure two cards as adhoc mode and connect each other successfully.  :)
    But, when I configured the card as tdma mode and set it as a master(tdmaslot 0), a few seconds later, the screen was full of:
"ath0: stuck beacon; resetting( bmiss count 4)"


    config commands:
ifconfig wlan0 create wlandev ath0 wlanmode tdma
ifconfig wlan0 ssid freebsd-tdma tdmaslotlen 2500 tdmaslot 0
ifconfig wlan0 up  (after this, "ath0: stuck beacon..." appears)


    If I set the card as a slave( tdmaslot 1), no these output messages. :(
    I tried to find the result from the code, it pointed to ath_hal_numtxpending(). (That means there are still frames pending in the QCU(AR5416)). But I didn't know why. 
    I searched it on the internet, many people experienced it, but none of them was the same case as mine.


    Then I reinstalled the OS with freebsd8.2-release. There was no "ath0: stuck beacon..."  :)
    But under freebsd8.2, I could not connect two cards as tdma mode either(no beacons send out). Oh~~ :(:(
    Card not support? OS not support? TDMA not support in 9.0 release? 
    Could you give me some advise, thanks a lot!


Best Wishes