From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261245AbVGTO4B (ORCPT ); Wed, 20 Jul 2005 10:56:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261341AbVGTOxo (ORCPT ); Wed, 20 Jul 2005 10:53:44 -0400 Received: from mail.metronet.co.uk ([213.162.97.75]:52960 "EHLO mail.metronet.co.uk") by vger.kernel.org with ESMTP id S261357AbVGTOwr (ORCPT ); Wed, 20 Jul 2005 10:52:47 -0400 From: Alistair John Strachan To: karim@opersys.com Subject: Re: Weird USB errors on HD Date: Wed, 20 Jul 2005 15:53:09 +0100 User-Agent: KMail/1.8.1 Cc: linux-kernel References: <42DD2EA4.5040507@opersys.com> In-Reply-To: <42DD2EA4.5040507@opersys.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200507201553.09602.s0348365@sms.ed.ac.uk> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 19 Jul 2005 17:47, Karim Yaghmour wrote: > I have a usb-attached HD that I use from time to time. When it's connected > to my desktop through a hub it works flawlessly. When connected to my Dell > D600 Laptop, however, it sometimes randomly exhibits a loud click (as if > the heads went berzerk) and the device goes unrecognized (i.e. the USB > layer drops the device and then redetects it again; meanwhile there is FS > corruption.) I've noticed my laptop is less able to output the required current for my portable HD than my desktop; either way it's probably not a good idea exceeding the USB specifications for current output @ 5V, so I'd recommend you use a powered hub or external PSU (if the HD supports one). Also a (slightly) nasty but functional trick is to have the power in when the HD initially spins up, then remove the power. Once the drive has spun up it seems to use a lot less power. You can get special USB cables that link two USB ports' 5Vs together in parallel, which seems to help supply the necessary current; after the HD has spun up you can remove the second "dummy" USB connector (my laptop only has two USB ports and I require the second port). -- Cheers, Alistair. personal: alistair()devzero!co!uk university: s0348365()sms!ed!ac!uk student: CS/CSim Undergraduate contact: 1F2 55 South Clerk Street, Edinburgh. EH8 9PP.