Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758895AbXFSQIv (ORCPT ); Tue, 19 Jun 2007 12:08:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753920AbXFSQIn (ORCPT ); Tue, 19 Jun 2007 12:08:43 -0400 Received: from h155.mvista.com ([63.81.120.155]:38321 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753723AbXFSQIm (ORCPT ); Tue, 19 Jun 2007 12:08:42 -0400 Message-ID: <4677FFF1.2010308@ru.mvista.com> Date: Tue, 19 Jun 2007 20:10:25 +0400 From: Sergei Shtylyov Organization: MontaVista Software Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803 X-Accept-Language: ru, en-us, en-gb MIME-Version: 1.0 To: Linas Vepstas Cc: Stuart_Hayes@Dell.com, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] ide dma_timer_expiry, then hard lockup References: <20070618175713.GD5836@austin.ibm.com> <4677E30B.4020101@ru.mvista.com> <20070619150502.GO5836@austin.ibm.com> In-Reply-To: <20070619150502.GO5836@austin.ibm.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1962 Lines: 48 Hello. Linas Vepstas wrote: >>Stuart_Hayes@Dell.com wrote: >>>I think reading the IDE status register clears the interrupt in the IDE >>>device, which might be causing the drive to think it's OK to generate >>>another interrupt. >> This is not how IDE drives are supposed to act -- they won't proceed any >>further until "interrupt pending" condition is cleared, so these aren't >>supposed to be "stacked". This behavior however is not strictly specified >>by ATA standards IIRC, but I can't readily imagine such situaltion anyway >>unless tagged command queueing (which is not supported by IDE core) and/or >>ATAPI command overlapping is in action... > The problem only manifests during high io load; perhaps a missing mutex > somewhere is blasting one thing too many out to the hard drive? Hm... not sure about this. >>>This could either cause it to get stuck trying to >>>service an interrupt that is never getting cleared as you suggested, or >>>possibly when the next IRQ comes in the IDE IRQ handler gets stuck >>>waiting for a spinlock that the code you're looking at already owns...? >> I could also imagine the HPT366 chip going mad and stalling the reads if >>the taskfile regs forever because of the incomplete DMA or even the drive >>going mad and not replying to I/O cycles with proper -IORDY handshake (i.e. >>holding it low all the time)... > In my case, ctrl-alt-sysrq doesn't work, which makes it hard to debug. > I'm thinking that trying to debug libata is a better idea, rather than > investing time in ide, right? Although at the moment, libata works even > less; see other email. Which makes me think this really is some *hardware* issue. > --linas MBR, Sergei - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/