[Voyage-linux] kernel: wifi0: stuck beacon; resetting (bmiss count 4)

[Andy S]

Been running Voyage (yes v. old ver.!) on this core node (hosted on reliable
old PIII pc!) on top of tower block for several years with essentially no
issues until yesterday when we suffered an attack of the infamous "stuck
beacon" issue (http://madwifi-project.org/wiki/StuckBeacon) causing outages
during ~11am - 15.30 see Cacti screencap below:

[image: outage06.07.11.png]

Sysinfo:

2.6.15-486-voyage #1 PREEMPT Mon Mar 27 07:45:05 GMT 2006 i686

using: madwifi-ng-modules-2.6.15-486-voyage

Wifi card (there are three others also but different to this one and
unaffected by this issue):

0000:04:08.0 0200: 168c:001b (rev 01)
       Subsystem: 168c:2063
       Flags: bus master, medium devsel, latency 168, IRQ 21
       Memory at 40000000 (32-bit, non-prefetchable) [size=64K]
       Capabilities: [44] Power Management version 2

PCI-ID = 168c 2063  EnGenius EMP-8602 (400mw) or Compex WLM54AG

*Above lspci info seems to conflict with comment posted (by previous
sysadmin no longer around) about card type used but no previous issues have
occurred similar to this...*

iwconfig ath0:

# NB Senao NMP-8602-PLUS card has antennae reversed, note antdiv diffs
auto ath0
iface ath0 inet static
        address ***.***.***.***  ## hidden for this post
        netmask 255.255.255.252
        wireless_channel 165
        wireless_essid *******  ## hidden for this post
        pre-up wlanconfig ath0 create wlandev wifi0 wlanmode ap && \
                sysctl -w dev.wifi0.diversity=0 && \
                sysctl -w dev.wifi0.txantenna=2 && \
                sysctl -w dev.wifi0.rxantenna=2
        up athctrl -i wifi0 -d 2190 && \
        tc qdisc add dev ath0 root handle 1: prio && \
        tc qdisc add dev ath0 parent 1:1 handle 10: sfq && \
        tc qdisc add dev ath0 parent 1:2 handle 20: sfq && \
        tc qdisc add dev ath0 parent 1:3 handle 30: sfq
        post-down wlanconfig ath0 destroy


At first we thought the issue was related to a bout of wet weather, but
investigation on the antenna didn't indicate this and logs showed stuck
beacon error.

Reading up on this it appears there isn't a known cause, but this snippet
from an Italian post (translated) suggests it is caused by interference from
other devices:

http://lublog.tuttoeniente.net/archives/151/fonera-4-eliminare-wifi0-stuck-beacon-resetting-bmiss-count-4
---------------------
Fonera # 4: Delete "wifi0: stuck beacon; resetting (bmiss count 4)"

You, too, you came, like me, the infamous "wifi0: stuck beacon; resetting
(bmiss count 4)" endlessly repeated in the output of dmesg ? The solution is
there, but not entirely painless.

The problem is due to a bug in the chipset drivers for Atheros wireless
interface of the Fonera, which manifests itself in particular in the
presence of other wireless devices, such as access points or other audio
video transmitters. For the record, I have both of these devices, then the
infamous error has always accompanied me, and even the classic solution to
set the network on channel 11 has solved the problem. This bug has been
fixed in newer versions of madwifi, but there is only one Fonera in the old
version.

<snip>...</snip>

(with a solution posted here relevant to Fonera)
-----------------------

All is back to normal today (despite more wet weather) so I'm wondering what
triggered this. Interestingly the lift engineer/s were present during this
episode and am beginning to suspect it is something related to them being in
the area. Wireless devices? A/V transmitting kit? Even presence of iPhone is
suggested in the Madwifi article above!!

What is the state of play with this? Anyone have similar experiences like
this?

I know upgrade is the usual reply and solution, but having read the Madwifi
page, in this case I am not sure, and don't want to try anything that could
break this otherwise rock solid box resulting in site visit!

Sorry for rather large post, but I am fascinated to find out the cause of
this - and any solution!

Thanks in advance,

A

--
http://www.bristolwireless.net/  | 0117 325 0067 |
sip:info at bristolwireless.net
Bristol Wireless
Windmill Hill City Farm
Philip Street
Bedminster
Bristol BS3 4EA
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