From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754915Ab0COHdL (ORCPT ); Mon, 15 Mar 2010 03:33:11 -0400 Received: from mail-ew0-f216.google.com ([209.85.219.216]:59311 "EHLO mail-ew0-f216.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752025Ab0COHdH convert rfc822-to-8bit (ORCPT ); Mon, 15 Mar 2010 03:33:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=gWUA+tUrll5VH6BqGGHoe04g9Ll5xeSyAmmCgS/nzuqh863VCz6EA/DezSyatVtLlv a3ZaJJHJDG9n/C96Gz73046+R7EWdFA1ZYKmMdDqP/ENN4cRtkYrKrnYXZfz3NqTe7qJ s7hIjcV2WwSAar3xfHqdrv0nvctQ710ZidVV4= MIME-Version: 1.0 In-Reply-To: <4B9DA1BB.9010808@garzik.org> References: <20100301202330.GA14977@havoc.gtf.org> <4B96C7B2.3080008@garzik.org> <4B971F83.4030505@kernel.org> <4B9DA1BB.9010808@garzik.org> Date: Mon, 15 Mar 2010 08:33:05 +0100 Message-ID: <40a4ed591003150033w5c416b28rfae989fa2ddf7305@mail.gmail.com> Subject: Re: [git patches] libata updates for 2.6.34 From: Zeno Davatz To: Jeff Garzik Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 15, 2010 at 3:55 AM, Jeff Garzik wrote: > On 03/09/2010 11:26 PM, Tejun Heo wrote: >> >> Hello, Linus, Jeff. >> >> On 03/10/2010 07:12 AM, Jeff Garzik wrote: >>> >>> Coincedentally, it looks like someone else just reported the same >>> problem, with 2.6.34-rc1. >>> >>> It definitely sounds like a race.  READ DMA is a DMA command as the name >>> implies, so that eliminates the possibility of polling-related paths in >>> ata_sff_interrupt (libata-sff.c). >>> >>> I'll flip some of my machines to the icky slow boring piix mode, rather >>> than sexy AHCI mode :) to see if I can reproduce.  I have had a feeling >>> that we needed a more sophisticated IRQ handling setup, this may be what >>> was needed.  Lost interrupt recovery should occur faster than 30 seconds >>> in any case, and should not require a hard reset if the hardware >>> functions just fine outside of the lost-interrupt / race that just >>> occurred. >> >> Yeap, there is a race condition with clearing which I don't think we >> can solve completely but with some modification I think we can at >> least cover known failure cases. >> >> For longer term, I don't think we can solve this by diddling with the >> SFF registers.  The interface is just way too ancient and horrid to >> build anything reliable on top of.  I'm planning on implementing >> smarter IRQ storm handling and stepped timeouts for ATA commands. > > A tester on this bug >        http://bugzilla.kernel.org/show_bug.cgi?id=15537 > seemed to find success with the patch. Thanks for the Update! I will wait some more and then test rc-2. Best Zeno