Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 13 Nov 2001 19:56:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 13 Nov 2001 19:56:31 -0500 Received: from modem-1461.leopard.dialup.pol.co.uk ([217.135.149.181]:10514 "EHLO Mail.MemAlpha.cx") by vger.kernel.org with ESMTP id ; Tue, 13 Nov 2001 19:56:22 -0500 Posted-Date: Wed, 14 Nov 2001 00:45:20 GMT Date: Wed, 14 Nov 2001 00:45:19 +0000 (GMT) From: Riley Williams Reply-To: Riley Williams To: Rob Turk cc: Matthew Dharm , Linux Kernel Subject: Re: PATCH: scsi_scan.c: emulate windows behavior In-Reply-To: <9srtm6$8hf$1@ncc1701.cistron.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Rob. > Getting more than 36 bytes should not be a problem for any device. > The root problem seems to be that 255 is an odd number. On > Wide-SCSI, a lot of devices have difficulty handling odd byte counts > as they have to use additional messaging to flag the residue in the > last 16-bit transfer. Also, the IDE-SCSI layer has trouble, as the > IDE spec doesn't allow odd byte transfers at all. I've experienced > issues with IDE devices that had to have their firmware patched just > to deal with the Linux odd-byte request. > Maybe a better change would be to use 64 or 128 byte requests. Your > thoughts? Probably the best option would be to tweak this to 256 if that is available, or 252 if not - I seem to remember there's at least one SCSI drive that can't handle other than multiples of 4 bytes. Best wishes from Riley. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/