atheros 'device timeout'

Sam Leffler sam at
Wed Jun 14 00:33:02 UTC 2006

Reid Linnemann wrote:
> I have a DWL-G520 with an atheros chipset on a 6-stable machine and I've 
> had a persistent problem for quite a long time now from 6-CURRENT in 
> 2005 to recent 6-stable that I need to address.
> First, I'll spit out pertinent machine information -
> uname -a:
> FreeBSD hautlos 6.0-STABLE FreeBSD 6.0-STABLE #3: Sat Mar 11 16:26:58 
> CST 2006     root at hautlos:/usr/obj/usr/src/sys/HAUTLOS  i386
> pciconf for the card:
> ath0 at pci0:12:0: class=0x020000 card=0x3a131186 chip=0x0013168c rev=0x01 
> hdr=0x00
>     vendor   = 'Atheros Communications Inc.'
>     device   = 'AR5212, AR5213 802.11a/b/g Wireless Adapter'
>     class    = network
> ifconfig ath0:
> ath0: 
> 1500
>         inet6 fe80::211:95ff:fe8d:1379%ath0 prefixlen 64 scopeid 0x3
>         ether 00:11:95:8d:13:79
>         media: IEEE 802.11 Wireless Ethernet autoselect mode 11g <hostap>
>         status: associated
>         ssid deutschland channel 6 bssid 00:11:95:8d:13:79
>         authmode OPEN privacy OFF txpowmax 36 protmode CTS ssid HIDE
>         dtimperiod 1 bintval 100
> The ath0 is briged to a dc0 interface through netgraph.
> This is the behavior I've noticed; at seemingly random intervals I will 
> get a device timeout thrown out to dmesg from the ath driver. Reading 
> the ath manpage, I see that "This should not happen." Most occurrences 
> do not yield any perceivable change in the connection. However, 
> sometimes the windows wireless clients I have associated with this 
> machine will not be able to receive anything over the wireless link 
> unless they trigger it by sending something over the radio. Sometimes 
> the windows clients will straight up lose track of the machine 
> completely and scan for other networks. I've not been able to replicate 
> the problem from a FreeBSD client.
> I desperately need to troubleshoot the problem, as my wife is getting 
> frustrated with losing connectivity to my "stupid computer" (which is 
> the gateway for our network) and I can't cook very well. ;) The 
> difficulty I'm having is that I don't know where to start to solve this 
> particular issue, and I've seen no other users with the same problem. 
> I'd appreciate any bumps in the correct direction.

There is a known issue w/ the buffering of multicast frames for 
associated stations operating in power save mode.  If this is the cause 
and you can disable power save operation in the clients you can 
workaround the problem.


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