From owner-freebsd-hackers@FreeBSD.ORG Thu Oct 16 18:30:02 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C837F1065687 for ; Thu, 16 Oct 2008 18:30:02 +0000 (UTC) (envelope-from mboxindia@gmail.com) Received: from gv-out-0910.google.com (gv-out-0910.google.com [216.239.58.185]) by mx1.freebsd.org (Postfix) with ESMTP id C82CE8FC19 for ; Thu, 16 Oct 2008 18:30:01 +0000 (UTC) (envelope-from mboxindia@gmail.com) Received: by gv-out-0910.google.com with SMTP id n8so77203gve.39 for ; Thu, 16 Oct 2008 11:30:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=/rOuEwqq/0TLMxhC/ZfRg5liMNGwBm5nBOvFeCtpx98=; b=wOxFS/p9AqOSZXCtiY7ZThUlKUOibneV+Kyy2oikhQeCOucnfaycBFem5slkB4RJmK gGLO131qYyJVpjQ66szabw7tIvXocg/V+a6BZ3nTmSC++uuyqmbJsu1nXWpvgdvN6lLw kG/5wI052BMOUyH/8FGm08YCMoxIP736Y74Zc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=AqK0K8e/6xT/qN1yYT5ETLqFkTdjpQyY/wJSrfYV5yJGJn7cmHv3Vq31gMMAtPKf05 GA+WezI4OJVpvh2lcECoMd7sqOutiY0PSgsdQCSmZP+KNIb0Ll0er/QuFvYmyVAK2SSU epNYiRjWSnYzxgHV93TIDOYf2W6xBeJ2Zc6cA= Received: by 10.103.222.12 with SMTP id z12mr1601310muq.95.1224181800267; Thu, 16 Oct 2008 11:30:00 -0700 (PDT) Received: by 10.103.141.5 with HTTP; Thu, 16 Oct 2008 11:30:00 -0700 (PDT) Message-ID: Date: Fri, 17 Oct 2008 00:00:00 +0530 From: Srinivas To: "Eduardo Morras" , "Pegasus Mc Cleaft" , freebsd-hackers@freebsd.org In-Reply-To: <20081015160522.04A824FEE1E@xroff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20081015160522.04A824FEE1E@xroff.net> Cc: Subject: Re: [Doubt] Can a PCI device communicate with another PCI or other device? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Oct 2008 18:30:02 -0000 I think a PCI device can communicate with another PCI device directly without the intervention of the CPU. Excerpt from "PCI Express System Architecture" ... PCI Transaction Model - Peer-to-Peer A Peer-to-peer transaction shown as Transaction 3 in Figure 1-5 on page 20 is the direct transfer of data between two PCI devices. A master that wishes to initiate a transaction, arbitrates, wins ownership of the bus and starts a transaction. A target PCI device that recognizes the address claims the bus cycle. For a write bus cycle, data is moved from master to target. For a read bus cycle, data is moved from target to master. .... --S On Wed, Oct 15, 2008 at 9:35 PM, Eduardo Morras wrote: > At 20:32 14/10/2008, you wrote: >> >> Hello, >> >> I have a small doubt. >> >> Suppose I have a PCI card with a general purpose CPU on it. Could it be >> able >> to communicate with another PCI device or ISA device(lets say IDE hard >> disk)? > > You can't do it directly. You must pass through the OS driver that controls > your card. You pass to your driver the data and it send data to other > driver, hard disk, etc.. Note that in some OSs your driver can't pass that > info from one driver to another and need an app that binds your driver with > the other driver. > > >> Thanks, >> Srinivas >> _______________________________________________ >> freebsd-hackers@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers >> To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > >