freebsd stable - Jul 2009 - ath0: stuck beacon; resetting (bmiss count 4)

I'me getting the message "ath0: stuck beacon; resetting (bmiss count
4)"
logged to syslog every so often. I have a Soekris net5501 with a Wistron
CM9  mini-PCI wireless card. I'm running FreeBSD 7.2-stable and "dmesg
|
grep ath0" gives:

ath0: <Atheros 5212> mem 0xa0010000-0xa001ffff irq 15 at device 17.0 on
pci0
ath0: [ITHREAD]
ath0: WARNING: using obsoleted if_watchdog interface
ath0: Ethernet address: 00:0b:6b:36:99:93
ath0: mac 5.9 phy 4.3 radio 3.6
ath0: ath_chan_set: unable to reset channel 6 (2437 Mhz, flags 0x490 hal
flags 0x150), hal status 12

I've seen Sam Leffler's reply to a previous question about the same log
message at
http://lists.freebsd.org/pipermail/freebsd-current/2009-March/004196.html.

Looking at the source code of if_ath.c in stable:

if (sc->sc_bmisscount > 3)        /* NB: 3 is a guess */
            taskqueue_enqueue(sc->sc_tq, &sc->sc_bstucktask);\

Now, in head the 3 has been made a variable but it doesn't seem to be
able to be tuned in any reasonable way.

I've tied increasing it to 20 and it doesn't seem to have any obvious
bad effects.

So, my questions:
- is 3 really a good guess?
- can it be increased safely?
- what sort of values should I try?
- are there any consequences of increasing it?
- could it be made a sysctl tunable?

Thanks for any help,
  Graham

Back in July, I asked the following on this list. I didn't get any replies.

I was running 7.2 at the time and the messages were coming up every
couple of minutes. Now I've upgraded to 8-RC1 and the same message is
coming out on the console every few seconds. The miss count limit is now
a sysctl tunable. I've increased it to 20 which slows the messages down
but they still happen. I then increased it to 2000 which has stopped
them completely. Although I did get a few "ath0: device timeout"
messages.

It seems to work correctly as a WPA2 AP.

Below is the contents of my hostapd.conf and the relevant lines from
rc.conf. Is this something to worry about? Can I improve it any way?

Thanks for any help,
  Graham

hostapd.conf:
interface=wlan0
debug=1
ctrl_interface=/var/run/hostapd
ctrl_interface_group=wheel
ssid=Menhennitt
wpa=2
wpa_passphrase=xxxxx
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP

rc.conf:
ifconfig_wlan0="inet xx.xx.xx.xx/25"
wlans_ath0="wlan0"
create_args_wlan0="wlanmode hostap mode 11g"
hostapd_enable="YES"

Graham Menhennitt wrote:
> I'me getting the message "ath0: stuck beacon; resetting (bmiss
count 4)"
> logged to syslog every so often. I have a Soekris net5501 with a Wistron
> CM9  mini-PCI wireless card. I'm running FreeBSD 7.2-stable and
"dmesg |
> grep ath0" gives:
>
> ath0: <Atheros 5212> mem 0xa0010000-0xa001ffff irq 15 at device 17.0
on pci0
> ath0: [ITHREAD]
> ath0: WARNING: using obsoleted if_watchdog interface
> ath0: Ethernet address: 00:0b:6b:36:99:93
> ath0: mac 5.9 phy 4.3 radio 3.6
> ath0: ath_chan_set: unable to reset channel 6 (2437 Mhz, flags 0x490 hal
> flags 0x150), hal status 12
>
> I've seen Sam Leffler's reply to a previous question about the same
log
> message at
> http://lists.freebsd.org/pipermail/freebsd-current/2009-March/004196.html.
>
> Looking at the source code of if_ath.c in stable:
>
> if (sc->sc_bmisscount > 3)        /* NB: 3 is a guess */
>             taskqueue_enqueue(sc->sc_tq, &sc->sc_bstucktask);\
>
> Now, in head the 3 has been made a variable but it doesn't seem to be
> able to be tuned in any reasonable way.
>
> I've tied increasing it to 20 and it doesn't seem to have any
obvious
> bad effects.
>
> So, my questions:
> - is 3 really a good guess?
> - can it be increased safely?
> - what sort of values should I try?
> - are there any consequences of increasing it?
> - could it be made a sysctl tunable?
>