From owner-freebsd-scsi@FreeBSD.ORG Sun May 6 17:04:02 2007 Return-Path: X-Original-To: scsi@freebsd.org Delivered-To: freebsd-scsi@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id AD85916A406 for ; Sun, 6 May 2007 17:04:02 +0000 (UTC) (envelope-from lydianconcepts@gmail.com) Received: from nz-out-0506.google.com (nz-out-0506.google.com [64.233.162.228]) by mx1.freebsd.org (Postfix) with ESMTP id 58E5213C483 for ; Sun, 6 May 2007 17:04:02 +0000 (UTC) (envelope-from lydianconcepts@gmail.com) Received: by nz-out-0506.google.com with SMTP id s1so1397904nze for ; Sun, 06 May 2007 10:04:01 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=dlTV5/Ru94Fp4c+35ct5Qw1SPq/tqeMIZG1zpKVk9571a2joA5Jvyd+S48N8NVOsifFbhLLKKpW1gBXiOJBcLWWA2ZVy20uX4CHJd97ZLeiAoXK6OwSGMyZT0cxBTv+oM9wFqLmEpMPXsHuyadBrMLFUKtp2LSGq8FjYaolXuag= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=MkRV7aAUEG0H9F1CsH2qKHlx7vwx+GrATvohbiScVJBdred5d8bYGVo+7tKKU5OiIUaOZHPRAjiKImRj8bPBCqHhP2lwYSu+zm5/PFTiYtR4Vidzycgbu/16uMcG/4l5z0fT893CnD4/8TT8tpDQj7QOfndba7p3Cy1NzCa4b/g= Received: by 10.115.92.2 with SMTP id u2mr1819377wal.1178471041242; Sun, 06 May 2007 10:04:01 -0700 (PDT) Received: by 10.114.25.18 with HTTP; Sun, 6 May 2007 10:04:01 -0700 (PDT) Message-ID: <7579f7fb0705061004p2c460887w227aad91795604cd@mail.gmail.com> Date: Sun, 6 May 2007 10:04:01 -0700 From: "Matthew Jacob" To: "Scott Long" In-Reply-To: <463DE4E7.1070506@samsco.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4628E0DE.2090103@samsco.org> <46290AC6.9020608@ask-us.at> <46292245.3030900@samsco.org> <463D9AAF.4070006@ask-us.at> <463DE4E7.1070506@samsco.org> Cc: Bernard Buri , scsi@freebsd.org Subject: Re: Upcoming plans for CAM X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 May 2007 17:04:02 -0000 A couple of comments here from me...... a) Other than architectural cleanliness, what advantages to FreeBSD will accrue to replacing the ata driver with CAM access? b) The NEW_TRAN code stuff is a way (not necessarily the cleanest) to try and be able to carry transport related metadata related to a periph. By and large the periph driver doesn't need to know transport related details. The exceptions to this are quirks which can only be safely derived from transport types and transport related values and identifiers that system management (or GEOM0 wants to know about (and really can only ask the periph driver about). c) All of #b is orthogonal to whether you have one periph driver or multiple periph drivers for the same fundamental 'type'. Perhaps the Win2K approach of allowing for selective binding (filter drivers) might be appropriate and would extend the current 'main' periph driver (e.g., "sa") plus the pass driver. d) Don't expect that ATA specific commands will just automatically tunnel, no matter what CAM changes are made. Different direct SATA controllers may have different requirements for being able to do arbitrary non-read/write commands. Tunneling HBAs (like mpt(4)) don't support the ATA passthrough CDB at all and instead require a special request structure. just a few random comments....