Return-path: Received: from mail.candelatech.com ([208.74.158.172]:39357 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753424Ab0IOOWD (ORCPT ); Wed, 15 Sep 2010 10:22:03 -0400 Message-ID: <4C90D683.7000801@candelatech.com> Date: Wed, 15 Sep 2010 07:21:55 -0700 From: Ben Greear MIME-Version: 1.0 To: Johannes Berg CC: Jouni Malinen , "linux-wireless@vger.kernel.org" Subject: Re: RFC: mac80211/ath9k: allow scanning single channel if other VIF is associated. References: <4C8EB03D.7070808@candelatech.com> <20100915030316.GB30253@jm.kir.nu> <4C9059DC.7060009@candelatech.com> <1284545796.3842.11.camel@jlt3.sipsolutions.net> In-Reply-To: <1284545796.3842.11.camel@jlt3.sipsolutions.net> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 09/15/2010 03:16 AM, Johannes Berg wrote: > On Tue, 2010-09-14 at 22:30 -0700, Ben Greear wrote: > >>> If I understood the change correctly, it would prevent running full >>> scans when in associated state. That does not sound reasonable behavior >>> and scanning should not cause an association to be lost. Did I miss >>> something or what exactly is this trying to do? >> >> That's pretty much what I'm trying to do. We had similar code in >> our 2.6.31 kernel with ath5k. Imagine getting 50 virtual stations >> started with WPA and all of them trying to scan all channels at once! > > They can't ... cfg80211 limits it to one scan at a time per hardware ... Right, but as soon as one finished, the next would start, and at least in .31, that caused the first to un-associate, giving never-ending loop of interfaces scanning and trying to associate. >> I think for the multi-VIF scenario, it should scan the single associated >> channel by default, but it would be nice to allow full scans on demand. > > Go change your userspace then to request only the single channel scan. > >> (I would very much like to work with standard wpa_supplicant, but if hacking it >> is the only way, then I can attempt that.) > > Yes, I don't see how we can reasonably work around this in the kernel. Ok, I'll see if I can add a 'scan-one-if-associated' flag for wpa-supplicant to use. Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com