Date: Sun, 18 Dec 2011 09:57:06 -0800 From: Kevin Oberman <kob6558@gmail.com> To: Joel Dahl <joel@freebsd.org> Cc: freebsd-wireless@freebsd.org Subject: Re: kern/163318: [ath] ath(4) stops working Message-ID: <CAN6yY1vCy%2BdTi%2BoVPLhK3=x-azOF1Bcojt2in=_YpyXsE9sJPw@mail.gmail.com> In-Reply-To: <201112181640.pBIGeFYS055210@freefall.freebsd.org> References: <201112181640.pBIGeFYS055210@freefall.freebsd.org>
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On Sun, Dec 18, 2011 at 8:40 AM, Joel Dahl <joel@freebsd.org> wrote: > The following reply was made to PR kern/163318; it has been noted by GNAT= S. > > From: Joel Dahl <joel@freebsd.org> > To: bug-followup@freebsd.org > Cc: > Subject: Re: kern/163318: [ath] ath(4) stops working > Date: Sun, 18 Dec 2011 17:35:18 +0100 > > =A0Disabling bgscan with > > =A0 ifconfig wlan0 -bgscan > > =A0fixes the problem. The machine has been running for 9 hours now withou= t any > =A0problems. I have been recommending that people having problems with wireless cards suddenly losing connectivity turn off bgscan for some time. It certainly fixed my problems with my old ath card, thought I am not sure that it is ath specific. I first reported this several years ago when Sam was still doing the ath work and received a prompt reply that I was wrong and bgscan was completely non-intrusive. I sent Sam details on exactly what I was seeing with the failures always occuring on the 5 minute intervals when background scans are done (though not at nearly every scan) and the conditions that triggered the problem and got a prompt response that what I was reporting was not possible and that whatever was causing the problems I was seeing was not bgscan. I have suggested turning off bgscan to many others reporting similar problems and gotten several responses that it worked. I am still convinced that something is not right about bgscan on FreeBSD, though I don't know if it is ath specific or more generally a wlan issue. I can say that it shows up most often when there are several APs with a common SSID showing up. I had particular problems when I was attending a large conference, such as NANOG, where there were several APs for a large room. I have no expertise on 802.11, so I can't tell much more, but I am convinced that something is wrong with bgscan on FreeBSD, at least with ath. I'd love to see someone get to the bottom of this. It has been showing up for at least 4 years and pre-dates the wlan split going back the the very early days of ath support. --=20 R. Kevin Oberman, Network Engineer E-mail: kob6558@gmail.com
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