From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH 1/3] Make the IDE DMA timeout modifiable Date: Fri, 13 Jul 2007 19:21:34 +0400 Message-ID: <4697987E.3040406@ru.mvista.com> References: <20070221011922.GA1777@freefall.freebsd.org> <200702210342.20775.bzolnier@gmail.com> <466EEFD6.9030001@ru.mvista.com> <200706160123.55636.bzolnier@gmail.com> <4693D9B6.4090408@ru.mvista.com> <20070713161612.2f2ebb0b@the-village.bc.nu> <46979652.6040201@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from h155.mvista.com ([63.81.120.155]:44334 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1755575AbXGMPTd (ORCPT ); Fri, 13 Jul 2007 11:19:33 -0400 In-Reply-To: <46979652.6040201@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Alan Cox , Bartlomiej Zolnierkiewicz , Suleiman Souhlal , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello. Mark Lord wrote: >> O> >> 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. :-) >> Because that value seemed to work ok. Mark set the timeouts way back in >> history and I never touched most of them. > > > I've lost the original question from this thread, but the idea of the The original question concerned specifically the DMA command timeout which is twice more than the usual one, WAIT_CMD (10 seconds). > longish > timeouts was that drive *may* be spun down ("standby"), and thus have to > spin > up again to complete media commands. Back then, drives were much slower at > spinning up than nowadays, and the ATA spec says to allow up to 30 seconds. Well, that doesn't explain the DMA case. MBR, Sergei