Return-path: Received: from mail.candelatech.com ([208.74.158.172]:43605 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756492Ab1CHUAI (ORCPT ); Tue, 8 Mar 2011 15:00:08 -0500 Message-ID: <4D768A9A.7090201@candelatech.com> Date: Tue, 08 Mar 2011 11:59:22 -0800 From: Ben Greear MIME-Version: 1.0 To: Brian Prodoehl CC: "Justin P. Mattock" , Mohammed Shafi , "John W. Linville" , linux-wireless@vger.kernel.org, Linux Kernel Mailing List , ath9k-devel@atheros.com Subject: Re: WARNING: at drivers/net/wireless/ath/ath9k/recv.c:536 ath_stoprecv+0xc8/0xda [ath9k]() References: <20110303135942.GA8969@tuxdriver.com> <20110307151201.GC2664@tuxdriver.com> <4D767A4B.1060203@gmail.com> <4D76833E.9010603@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 03/08/2011 11:45 AM, Brian Prodoehl wrote: > On Tue, Mar 8, 2011 at 2:27 PM, Ben Greear wrote: >> On 03/08/2011 10:49 AM, Justin P. Mattock wrote: >>> >>> On 03/07/2011 07:22 AM, Mohammed Shafi wrote: >>>> >>>> On Mon, Mar 7, 2011 at 8:42 PM, John W. >>>> Linville wrote: >>>>> >>>>> On Sun, Mar 06, 2011 at 12:47:05AM -0800, Justin Mattock wrote: >>>>> >>>>>> full dmesg here: >>>>>> http://fpaste.org/5JQp/ >>>>>> let me know if I need to supply any info(also I can try a bisect, but >>>>>> am in the middle of changing residencies, so it might not be right >>>>>> away) >>>>> >>>>> One of the Atheros guys suggested that you change a DMA timeout value. >>>>> Did you try that? >>>> >>>> John it looks like increasing the timeout also does not seems to help. >>>> A user reported this issue in ath9k developer list and he told that >>>> increasing the timeout did not fix this issue. >>>> >>>>> >>>>> John >>>>> -- >>>>> John W. Linville Someday the world will need a hero, and you >>>>> linville@tuxdriver.com might be all we have. Be ready. >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe >>>>> linux-wireless" in >>>>> the body of a message to majordomo@vger.kernel.org >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>> >>>> >>> >>> at barnes and noble, and I see this has fired off again. will see if I >>> can reproduce and bisect. >> >> This problem goes way back, and the driver has had lots of fixes in the >> last few months, so I'm not sure if bisecting is going to >> do you any good. >> >> Thanks, >> Ben > > The warnings have been around since you added the check for the > problem, right? I remember initially it was a WARN_ON, and I'd get a > steady flood of backtraces, and then it was switched to a > WARN_ON_ONCE. I see these on every platform I have (x86_64, IXP425 > and AR71xx) with AR9002 and AR9003. I don't think I added the original check, but either way, it's an old problem and bisecting it is unlikely to help. I can't believe that the Atheros guys really are unable reproduce this, but I can believe that it might be very difficult to actually understand and fix. At least in my testing, I see it quite often, but it doesn't seem to cause any serious harm. We do occasionally see crashes, especially on module unload for a heavily utilized system, or one that is constantly trying and failing to associate, so it could be related to this. Also, my patches to decrease scan and work_work related channel changes made this harder to hit for our test cases. Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com