Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932235AbVLANof (ORCPT ); Thu, 1 Dec 2005 08:44:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932234AbVLANof (ORCPT ); Thu, 1 Dec 2005 08:44:35 -0500 Received: from magic.adaptec.com ([216.52.22.17]:163 "EHLO magic.adaptec.com") by vger.kernel.org with ESMTP id S932226AbVLANoe convert rfc822-to-8bit (ORCPT ); Thu, 1 Dec 2005 08:44:34 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.0.6487.1 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: [PATCH] aic79xx should be able to ignore HostRAID enabled adapters Date: Thu, 1 Dec 2005 08:44:15 -0500 Message-ID: <547AF3BD0F3F0B4CBDC379BAC7E4189F01E3E318@otce2k03.adaptec.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH] aic79xx should be able to ignore HostRAID enabled adapters Thread-Index: AcX2ah5JPoCeAYzVQGOrlrUKrBbaMAADfx9A From: "Salyzyn, Mark" To: "Christoph Hellwig" , "Darrick J. Wong" Cc: "Chris McDermott" , "Luvella McFadden" , "AJ Johnson" , "Kevin Stansell" , , , Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2484 Lines: 56 Christoph Hellwig sez: > NACK. We're not going to support attaching broken propritary drivers. Understood and expected. The word 'broken' is hardly chosen for scientific reasons, bespeaks an agenda ;-> Just because you can not see the code, does not mean it is broken. I have on numerous attempts tried to contact Heinz Mauelshagen to fortify dmraid in support of the HostRAID adapters. He has yet to respond to my emails to start a dialogue with Adaptec. Justin Gibbs had provided the community the emd driver, soundly rejected and never ported to dm because there were features that Justin held dear in md that do not translate to dm. An unfortunate waste of considerable resources. Without the timely agenda and cooled temperaments to close the gap, the solution should be temporarily to support the proprietary HostRAID driver when the Adapter is in HostRAID mode and we continue to work to close that gap on dmraid. Could you agree with that to help the users today? [ You are on record as not giving a fig for the users, what if I showed them as starving children in a third world nation, would that melt your heart? ;-} ] > Sepcially as these "HostRAID" cards are plain SCSI HBAs. They are plain SCSI HBAs, but are designated as a RAID card rather than a Host Bus Adapter in the PCI config space when in 'HostRAID' mode. The fact that is designated in the PCI space should be enough reason *not* to attach a simplified LLD. The HostRAID driver has a specialized (ok, yes, also proprietary) CHIM and sequencer where attention can be focused on techniques of performance improvement and OS agnostics. In addition, the RAID code in that driver understands the hardware, CHIM & sequencer and takes advantage of features that just can not be performed by an abstracted dm or an LLD. RAID1 is handled under some conditions, for instance, with one DMA operation over the PCI bus rather than two duplicated for each target, greatly increasing the performance. Linux is not about performance first, it is about doing it the Linux way. I believe we can understand that. And in turn, do not consider it harmful if a group of individuals trying to make a living see a chance to acquire a competitive edge. Sincerely -- Mark Salyzyn - 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/