From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: ata_piix and combined mode Date: Mon, 22 Mar 2004 13:15:40 -0500 Sender: linux-ide-owner@vger.kernel.org Message-ID: <405F2D4C.9010506@pobox.com> References: <20040322132336.GA12460@cistron.nl> <405F2B2E.6080001@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:44261 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262165AbUCVSPx (ORCPT ); Mon, 22 Mar 2004 13:15:53 -0500 In-Reply-To: <405F2B2E.6080001@pobox.com> List-Id: linux-ide@vger.kernel.org To: Miquel van Smoorenburg Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Bartlomiej Zolnierkiewicz Jeff Garzik wrote: > c) hardware pretends that SATA0/1 are master/slave. > This last introduces nastiness into most drivers, since sata > is _really_ point-to-point. Faking non-PTP this way leads > to a disconnect, because you must now map master to > port 0 or 1, and slave to the other port (yes ordering > is dynamic too). Just to be more clear, the assignment (routing) of PATA and SATA ports on the ICH5 too dynamic for its own good. You must deal with * PATA and SATA on separate PCI devices (as it should be) * PATA and SATA on the same PCI device, where c0 == pata0 master (master), pata1 master (slave) c1 == sata0 (master), sata1 (master) or c0 == pata0 master (master), pata1 master (slave) c1 == sata1 (master), sata0 (master) the ICH6 follows the horror of combined mode, where c0 or c1 might be sata ports 0/2 or 1/3 (it has 4 sata ports rather than ICH5's 2). and PATA might be c0 or c1. (c0 == ata channel zero, c1 == ata channel one) Sigh. Although not with libata, with other drivers I belive that combined mode is fundamentally flawed. Pretending a SATA device is a PATA device eliminates SATA-specific knowledge, such as avoiding soft-reset (SRST) on certain SATA devices, since they will lock up on probe. I always recommend that users avoid combined mode when their configuration permits. Jeff