Atheros Looping: ath0: hardware error; resetting

Sam Leffler sam at errno.com
Sat Dec 17 11:28:19 PST 2005


Nate Nielsen wrote:
> I have Atheros 5213 based 802.11a cards. When switching 'media' (ie:
> rates or speed) I often get the following error multiple times on my
> console:
> 
> 
>>ath0: hardware error; resetting
>>ath0: hardware error; resetting
> 
> 
> It's all fine and good when it's just a few times, but in many cases it
> enters an endless loop, bringing the wireless link to it's knees. The
> above line is written to the console over and over again,
> 
> I'm running FreeBSD 6.0 on two boxes sitting next to each other. The
> wireless NICs are setup real simple (in rc.conf) with:
> 
> ifconfig_ath0="inet 10.28.2.18/30 ssid tel2 channel 52 \
>                mediaopt adhoc"
> 
> To duplicate run the following several times:
> 
> # ifconfig ath0 media auto
> # ifconfig ath0 media OFDM/6Mbps
> 
> A work around is simply to punch the settings into rc.conf and reboot.

Seems to work fine here with CURRENT; I just typed the exact commands 
from above.  "hardware errors" are typically dma errors.  If you're 
operating in adhoc mode the h/w is periodically sending beacons and if 
that tx descriptor gets setup wrong it can cause a dma error.  Marking 
the interface down will shutdown all dma so if you're seeing these 
repeat try doing that.  Perhaps there is a race in changing state but I 
just did a tight loop where I switched media and saw nothing bad happen.

I can try 6.0 later.  FWIW 5213 is kinda nebulous; the only true info 
are the mac+phy revs from dmesg|grep ath.

	Sam


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