From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH ide] : Increase WAIT_DRQ to support slow CF cards Date: Tue, 27 Oct 2009 13:24:48 +0300 Message-ID: <4AE6CA70.3000002@ru.mvista.com> References: <51f3faa70910261807h54f05f73j48b67067ee3dde70@mail.gmail.com> <20091026.181922.261475236.davem@davemloft.net> <51f3faa70910261840v16444067uc323de7129b7592f@mail.gmail.com> <20091026.184318.205708741.davem@davemloft.net> <20091027094503.GA3116@frolo.macqel> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from gateway-1237.mvista.com ([206.112.117.35]:58726 "HELO imap.sh.mvista.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1752760AbZJ0KY6 (ORCPT ); Tue, 27 Oct 2009 06:24:58 -0400 In-Reply-To: <20091027094503.GA3116@frolo.macqel> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Philippe De Muyter Cc: David Miller , hancockrwd@gmail.com, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello. Philippe De Muyter wrote: >> From: Robert Hancock >> Date: Mon, 26 Oct 2009 19:40:03 -0600 >> >> >>> On Mon, Oct 26, 2009 at 7:19 PM, David Miller wrote: >>> >>>> Meanwhile we should provide a way for things to work, and >>>> realistically the only way to do that currently is to bump the >>>> WAIT_DRQ value to some large number. >>>> >>>> And that's exactly the kind of patch I'm willing to accept for this. >>>> >>> I agree, it's sub-optimal but it helps.. if the user wants better >>> behavior they should a) fix it so that the card isn't using PIO, at >>> least if it supports DMA and b) not use drivers/ide.. >>> > > Strangely enough, I also had no timeout problem if I started my kernel with > 'ide=nodma', instead of increasing WAIT_DRQ. Hm, interesting... > So I surmise that WAIT_DRQ is used in the dma case. > > It's used only for the PIO write commands -- see do_rw_taskfile() in ide-taskfile.c... DMA commands don't require waiting for BSY=0, DRQ=1 condition. > Philippe > WBR, Sergei