From owner-freebsd-arch@FreeBSD.ORG Fri Jun 5 16:58:32 2009 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 57CD71065705; Fri, 5 Jun 2009 16:58:32 +0000 (UTC) (envelope-from mav@mavhome.dp.ua) Received: from cmail.optima.ua (cmail.optima.ua [195.248.191.121]) by mx1.freebsd.org (Postfix) with ESMTP id 9F8AC8FC0A; Fri, 5 Jun 2009 16:58:31 +0000 (UTC) (envelope-from mav@mavhome.dp.ua) Received: from [212.86.226.226] (account mav@alkar.net HELO mavbook.mavhome.dp.ua) by cmail.optima.ua (CommuniGate Pro SMTP 5.2.9) with ESMTPSA id 245042309; Fri, 05 Jun 2009 19:58:28 +0300 Message-ID: <4A294EAF.3080706@mavhome.dp.ua> Date: Fri, 05 Jun 2009 19:58:23 +0300 From: Alexander Motin User-Agent: Thunderbird 2.0.0.21 (X11/20090405) MIME-Version: 1.0 To: Matthew Dillon References: <4A254B45.8050800@mavhome.dp.ua> <200906050703.n5573x5Q071765@apollo.backplane.com> <200906051601.n55G10Mi075734@apollo.backplane.com> In-Reply-To: <200906051601.n55G10Mi075734@apollo.backplane.com> Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit Cc: FreeBSD-Current , freebsd-arch@freebsd.org Subject: Re: WIP: ATA to CAM integration X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Jun 2009 16:58:33 -0000 Matthew Dillon wrote: > It's unclear to me what this means. Can we use NCQ to queue multiple > commands to multiple ports behind a single port multiplier in parallel > or can't we? It's very confusing. As I have said, without controller FIS Based Switching capability it is impossible. FBS defines separate memory areas for controller, to track there state of each drive behind PM. Without it, only one drive can be active at a time, as controller will not be able to track when each drive is able to receive next command.. -- Alexander Motin