From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761852AbXGJTI4 (ORCPT ); Tue, 10 Jul 2007 15:08:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756678AbXGJTIq (ORCPT ); Tue, 10 Jul 2007 15:08:46 -0400 Received: from gateway-1237.mvista.com ([63.81.120.155]:16039 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752852AbXGJTIp (ORCPT ); Tue, 10 Jul 2007 15:08:45 -0400 Message-ID: <4693D9B6.4090408@ru.mvista.com> Date: Tue, 10 Jul 2007 23:10:46 +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: Bartlomiej Zolnierkiewicz Cc: Suleiman Souhlal , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] Make the IDE DMA timeout modifiable References: <20070221011922.GA1777@freefall.freebsd.org> <200702210342.20775.bzolnier@gmail.com> <466EEFD6.9030001@ru.mvista.com> <200706160123.55636.bzolnier@gmail.com> In-Reply-To: <200706160123.55636.bzolnier@gmail.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 Hello. Bartlomiej Zolnierkiewicz wrote: >>>>On Feb 20, 2007, at 5:44 PM, Bartlomiej Zolnierkiewicz wrote: >>>>>On Wednesday 21 February 2007 02:19, Suleiman Souhlal wrote: >>>>>>It can be changed via /proc/ide/hd?/settings. >>>>>Why do we need to change IDE DMA timeout dynamically? >>>>I've used it to test error recovery (for example). >>>Seems quite useable for developers but I would prefer not to >>>expose it in production kernels for end users. >> It seems that I have counter example of a customer asking if this timeout >>can be done configurable. :-) > May I ask what was the rationale for this request? Their system seems to become unschedulable for this period of time (DMA timeouts happen from time to time) -- at least the keepalive daemon stopped replying during this period... > I have no strong feelings about adding this /proc/ide/ setting but I worry > that it could be (mis)used just to (unreliably) work-around problems... >> BTW, why the timeout is so damn long? 2*WAIT_CMD is 20 secs, and if DMA is >>not complete or interrupt pending, it may wait 10 more secs... > I really don't remember... :) > Maybe Mark or Alan could help with figuring this out. They also have probably forgotten. :-) > Thanks, > Bart MBR, Sergei