On Fri, May 02, 2008 at 05:25:09PM -0700, Sam Leffler wrote:
> Petar Bogdanovic wrote:
>> Hi,
>>
>> I'm using an alix2c0 board with two winstron CM9 ath(4)-cards and
>> FreeBSD 7:
>>
>> ifconfig ath0 (...) mediaopt hostap mode 11a channel 36 ssid sn.a
>> -bgscan
>> ifconfig ath1 (...) mediaopt hostap mode 11g channel 11 ssid sn.g
>> -bgscan
>>
>>
>> When I try to raise the traffic (i.e. dd | ssh AP dd) my Linux
>> wpa_supplicant drops the connection and has to reassociate. This however
>> does not work immediately; The supplicant fails a few times before
>> reconnecting:
>>
>> <2>CTRL-EVENT-CONNECTED - Connection to 00:0b:0b:06:0d:09 completed
>> (reauth) [id=0 id_str=]
>> <2>CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Authentication with 00:0b:0b:06:0d:09 timed out.
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Authentication with 00:0b:0b:06:0d:09 timed out.
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Authentication with 00:0b:0b:06:0d:09 timed out.
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Authentication with 00:0b:0b:06:0d:09 timed out.
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Authentication with 00:0b:0b:06:0d:09 timed out.
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Authentication with 00:0b:0b:06:0d:09 timed out.
>> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320
>> MHz)
>> <2>Associated with 00:0b:0b:06:0d:09
>> <2>WPA: Key negotiation completed with 00:0b:0b:06:0d:09 [PTK=CCMP
>> GTK=CCMP]
>> <2>CTRL-EVENT-CONNECTED - Connection to 00:0b:0b:06:0d:09 completed
>> (reauth) [id=0 id_str=]
>>
>>
>> This happens more on the 11a than on the 11g network. When I'm next to
>> the AP, the timeouts are almost gone but they still happen. (My laptop
>> is just one room away from the AP). Here is the athstats-output of ath0
>> (11a):
>>
>> # ./athstats -i ath0
>> 481546 data frames received
>> 330669 data frames transmit
>> 13395 tx frames with an alternate rate
>> 78558 long on-chip tx retries
>> 1431 tx failed 'cuz too many retries
>> 36M current transmit rate
>> 78 tx management frames
>> 3 tx frames discarded prior to association
>> 45 tx frames with no ack marked
>> 2894 rx failed 'cuz of bad CRC
>> 2 rx failed 'cuz decryption
>> 92711 rx failed 'cuz of PHY err
>> 92708 OFDM timing
>> 3 OFDM restart
>> 318332 beacons transmitted
>> 1111 periodic calibrations
>> 2 rfgain value change
>> 22 rssi of last ack
>> 23 avg recv rssi
>> -96 rx noise floor
>> 2530 switched default/rx antenna
>> Antenna profile:
>> [1] tx 173364 rx 123068
>> [2] tx 155874 rx 358671
>
> So the obvious question is whether your system config has enough isolation
> of the radios for them not to impact each other? I have no experience with
> Alix boards but it's not uncommon for there to be power and signal issues
> when operating multiple radios in an enclosure (and yes, even with the
> radios on different bands).
>
> You don't indicate what you've done to diagnose this problem. Have you
> verified the packets are present in the air? Have you traced packets
> and/or phy errors around the time of the problem? Does turning off one
> radio give you stable operation? Have you tried different channels? Have
> you tried different boards?
>
>
>>
>>
>> All this is well known to me, since I had NetBSD running on this device
>> for months and it suffered the same problems -- it was even worse, the
>> timeouts occured every few minutes. Back then, it seemed that ath had
>> some interrupt problems:
>>
>> ath0: device timeout
>>
>> as David Young from NetBSD noticed in his mail some time ago:
>>
>> http://mail-index.netbsd.org/tech-net/2007/11/29/0001.html
>>
>>
>> FreeBSD doesn't seem to have this `device timeouts'. I don't see any in
>> /var/log/messages and there are none when I'm connected to the device
>> over a serial port.
>>
>> I'm a bit lost here, but ready to debug if someone knows more.
>
> netbsd's code base is many _years_ out of date wrt freebsd; comparing
> operation of the two systems is unlikely to be useful.
Just for the record:
After various (client-)tests with Intel 2200BG and 3945ABG chips and one
AR5212 chip on FreeBSD, it seems that only the madwifi client caused
interrupts or more precisly: interrupts after a missed beacon.
My observations correspond with the following madwifi ticket:
http://madwifi.org/ticket/848
One beacon miss, one interrupt. The FreeBSD ath-driver does _not_ show
any similar behaviour on the same device.
Kind regards,
Petar
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