From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rogier Wolff Subject: Re: Driver retries disk errors. Date: Tue, 31 Aug 2004 00:25:45 +0200 Sender: linux-ide-owner@vger.kernel.org Message-ID: <20040830222545.GB31968@bitwizard.nl> References: <20040830163931.GA4295@bitwizard.nl> <20040830174632.GA21419@thunk.org> <41337153.60505@superbug.demon.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from users.linvision.com ([62.58.92.114]:27274 "HELO bitwizard.nl") by vger.kernel.org with SMTP id S264668AbUH3WZt (ORCPT ); Mon, 30 Aug 2004 18:25:49 -0400 Content-Disposition: inline In-Reply-To: <41337153.60505@superbug.demon.co.uk> List-Id: linux-ide@vger.kernel.org To: James Courtier-Dutton Cc: Theodore Ts'o , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org On Mon, Aug 30, 2004 at 07:26:27PM +0100, James Courtier-Dutton wrote: > It does the same retries with CD-ROM and DVDs, and if the retries fail, > it disables DMA! As a matter of fact, we've had a computer where I tried to get an MFM drive working. There I had changed lots of settings in the BIOS to disable the onboard IDE and stuff like that. When we tried to get IDE back working, we encountered the situation where the secondary channel would not DMA unless . There the strategy "disable DMA" works: the drive is "switched down" and something works. I remember from the old days that this was: "To enable the user to continue to use the system to fix the problem". However, in practise, this failure is not something that you can fix "if you have access to your drive", but something you get to fix in the BIOS. So does this still help? Well, maybe PIO is so "basic" that it will always work, and is a good "last resort'. The "same retries with CDROM" stems from the fact that the code was initially duplicated. (as in cp ide-disk.c ide-cd.c) The fact that DVDs are nowadays writable should be a hint that the drivers may be better off getting merged one of these days. Roger. -- +-- Rogier Wolff -- www.harddisk-recovery.nl -- 0800 220 20 20 -- | Files foetsie, bestanden kwijt, alle data weg?! | Blijf kalm en neem contact op met Harddisk-recovery.nl!