Problems running ath with bgscan enabled

[Sam Leffler]

Alexandre "Sunny" Kovalenko wrote:
> On Sat, 2007-10-20 at 20:02 -0700, Sam Leffler wrote:
>> Kevin Oberman wrote:
>>> Ever since the update of the HAL and the new 802.11 code a few months
>>> ago (in current), I have been having problems, especially when I was in
>>> locations with multiple APs available. 
>>>
>>> The problem was periodic loss of association. If I was at home where I
>>> can usually only see a couple of APs, the problem would occur an
>>> average of about 10 times a day with re-association in about 10 seconds,
>>> sometimes less. This is annoying, but not very disruptive.
>>>
>>> When away from home and in an urban location where there are several
>>> APs, both the frequency of the loss of connectivity and the time to
>>> re-associate increase. Last week at the NANOG meeting there were 4
>>> conference b/g APs and 4 11a APS seen at all times along with the
>>> hotel's tmobile and a couple of random ones. Only the two conference
>>> SSIDs (nanog-arin and nanog-arin-a) were in my wpa_supplicant.conf
>>> file. 
>>>
>>> My bgscan interval was the default 300 and almost every 5 minutes I
>>> would lose connectivity, often for over a minute. When I made the
>>> association between the bgscan interval and the drop-outs, I did an
>>> "ifconfig ath0 -bgscan" and things stabilized immediately. No further
>>> problems. 
>>>
>>> ath_hal: 0.9.20.3 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)
>>> ath0: <Atheros 5212> mem 0xb4000000-0xb400ffff irq 11 at device 2.0 on pci11
>>> ath0: mac 5.9 phy 4.3 radio 3.6
>>>
>>> This is really not acceptable for default behavior as it won't be clear
>>> to many how to fix it. Is it expected or is something wrong?
>>>
>>> Thanks!
>> There hasn't been a hal change in a long time.  bgscan works by telling
>> the ap your station is in power save mode, leaving the channel briefly,
>> and then returning.  I have not seen any issues with it w/ or w/o
>> wpa_supplicant.
>>
>> Maybe you can provide some information to help diagnose this?  I see
>> nothing helpful like a log from wpa_supplicant or statistics.
>>
>> 	Sam
>> _______________________________________________
>> freebsd-mobile at freebsd.org mailing list
>> http://lists.freebsd.org/mailman/listinfo/freebsd-mobile
>> To unsubscribe, send any mail to "freebsd-mobile-unsubscribe at freebsd.org"
> This is "me too" and the question. The question is: where did sysctl
> dev.ath.0.debug go? I have defined ATH_DEBUG in if_ath.c and rebuilt the
> module, but id did not seem to appear. I understand that log, produced
> with that sysctl set to 0x00040000, would be the first thing you need to
> look into the issue, so if you would nudge me in the proper direction, I
> will be happy to produce it. I have two stations in my house and
> experience the problem, Kevin describes, on the regular basis. Turning
> off bgscan helped enormously (thank you, Kevin).
> 

ath debug msgs are at the wrong level, you want things at the net80211
layer.  I can't tell you why you're having problems turning on ath debug
msgs, I do it all the time either by setting ATH_DEBUG in a kernel
config file or in the module Makefile.

	Sam