Return-path: Received: from mail.candelatech.com ([208.74.158.172]:45591 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753234Ab0LFUWd (ORCPT ); Mon, 6 Dec 2010 15:22:33 -0500 Message-ID: <4CFD4602.1030304@candelatech.com> Date: Mon, 06 Dec 2010 12:22:26 -0800 From: Ben Greear MIME-Version: 1.0 To: =?ISO-8859-1?Q?Bj=F6rn_Smedman?= CC: "Luis R. Rodriguez" , Felix Fietkau , Luis Rodriguez , "ath9k-devel@lists.ath9k.org" , "linux-wireless@vger.kernel.org" Subject: Re: [ath9k-devel] Script to crash ath9k with DMA errors. References: <4CF44543.9070605@candelatech.com> <20101130004424.GC1901@tux> <4CF6D8C8.2000308@candelatech.com> <4CF8A6DE.4020804@candelatech.com> <4CFAFBE1.3080505@openwrt.org> <4CFB20BA.5090300@candelatech.com> <20101206193600.GC21442@tux> <4CFD3DE3.4000207@candelatech.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/06/2010 12:11 PM, Bj?rn Smedman wrote: > On Mon, Dec 6, 2010 at 8:47 PM, Ben Greear wrote: >> With 16 properly configured non-encrypted stations, running with >> wpa-supplicant >> with netlink driver& sharing scan results, the interfaces quickly >> associate. >> >> However, I do continue to see DMA warnings such as these (I had picked up my >> portable phone, and it knocked all the interfaces offline ..here >> they are coming back up after I hung up the phone). > > Is there some theory as to why using multiple interfaces cause so many > problems with DMA? Seems pretty directly related to channel changes and/or resets, and exacerbated by other interfaces sending data while another is scanning, for instance. Other issues we've found in the past have been various races that you wouldn't normally see with a single VIF. Thanks, Ben > > /Bj?rn -- Ben Greear Candela Technologies Inc http://www.candelatech.com