From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755085AbYDIMBQ (ORCPT ); Wed, 9 Apr 2008 08:01:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752843AbYDIMBB (ORCPT ); Wed, 9 Apr 2008 08:01:01 -0400 Received: from mail.hevs.ch ([153.109.23.10]:55134 "EHLO mail.hevs.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752406AbYDIMBA (ORCPT ); Wed, 9 Apr 2008 08:01:00 -0400 From: Marc Pignat Organization: HEVs To: Haavard Skinnemoen Subject: Re: [BUG, bisected] atmel_spi: hard lockups in transfer Date: Wed, 9 Apr 2008 14:00:55 +0200 User-Agent: KMail/1.9.9 Cc: Ben Nizette , kernel , slipszi@gmail.com, linux-kernel References: <1207438118.3319.8.camel@moss.renham> <20080406181817.5824f962@siona.local> In-Reply-To: <20080406181817.5824f962@siona.local> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200804091400.56727.marc.pignat@hevs.ch> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 07 April 2008, Haavard Skinnemoen wrote: > On Sun, 06 Apr 2008 09:28:38 +1000 > Ben Nizette wrote: > > > Hi, > > > > For some weeks now there have been reports flying across the main AVR32 > > support forum, avrfreaks [1], that atmel_spi now hard-hangs on most > > transfers. The behaviour is not apparent in .23 and is in .24+. One > > tester was good enough to bisect the problem and turned up > > Thanks for reporting this. > > > 154443c72f47169ebcb3a7befbff0e934c49bff3 > > atmel_spi: chain DMA transfers > > > > as the culprit. The tester also had to revert > > > > commit 8bacb219018a52e6f02a3cff6a7badf102ddfc44 > > atmel_spi: fix dmachain oops with DEBUG enabled > > > > when they reverted 154443 as they were not confident enough to resolve > > the conflicts that resulted from just reverting the first one. > > That is indeed the correct way to resolve the conflict since the latter > fixes a bug introduced by the former. > > > The discussion thread involving this can be seen at [2]. > > > > As I say, this is present in .24+ so any fix will be a stable candidate > > as well as .25 material (if we haven't missed the boat by then). mainline .24+ is not affected (linux-2.6.24.3.atmel.3.tar.bz2 is). > > I'm afraid I don't have much time to look at this right now...but I'll > see what I can do. It's strange that I never noticed this problem > myself -- I did see some overrun issues, but I blamed it on the > throughput improvements and just reduced the speed slightly. This patch seems to have problems at least on avr32, since this is only a speed-up patch, we should revert them. Regards Marc