From owner-freebsd-wireless@FreeBSD.ORG Sun Dec 18 18:20:46 2011 Return-Path: Delivered-To: freebsd-wireless@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CD4851065672; Sun, 18 Dec 2011 18:20:46 +0000 (UTC) (envelope-from kob6558@gmail.com) Received: from mail-ww0-f42.google.com (mail-ww0-f42.google.com [74.125.82.42]) by mx1.freebsd.org (Postfix) with ESMTP id 38AF28FC1E; Sun, 18 Dec 2011 18:20:45 +0000 (UTC) Received: by wgbds13 with SMTP id ds13so6148401wgb.1 for ; Sun, 18 Dec 2011 10:20:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=/u3d+om0dbM3xLTd7OAVrW0FY0LsgZR+7sz5OSsuFC8=; b=wZfw9fnG0XtvNcMXUbXTYYLnrrfAZMjhXFivg56ji+Y81V5Okjf8ZFehClENLZzJCl u4Lt3OiCVM5N3OeMnViWVQMMiAOT05NwR8Ji0vVe3LimxHCEpcG/VIfr20HFaUacfAnp TwdnICTYoGr+XaEZZ0VfB3UKKfb0icJy/CeQ0= MIME-Version: 1.0 Received: by 10.180.95.136 with SMTP id dk8mr18233241wib.11.1324231026081; Sun, 18 Dec 2011 09:57:06 -0800 (PST) Received: by 10.223.158.129 with HTTP; Sun, 18 Dec 2011 09:57:06 -0800 (PST) In-Reply-To: <201112181640.pBIGeFYS055210@freefall.freebsd.org> References: <201112181640.pBIGeFYS055210@freefall.freebsd.org> Date: Sun, 18 Dec 2011 09:57:06 -0800 Message-ID: From: Kevin Oberman To: Joel Dahl Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-wireless@freebsd.org Subject: Re: kern/163318: [ath] ath(4) stops working X-BeenThere: freebsd-wireless@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Discussions of 802.11 stack, tools device driver development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Dec 2011 18:20:46 -0000 On Sun, Dec 18, 2011 at 8:40 AM, Joel Dahl wrote: > The following reply was made to PR kern/163318; it has been noted by GNAT= S. > > From: Joel Dahl > 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