From owner-svn-src-all@FreeBSD.ORG Fri Mar 2 22:21:55 2012 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 86271106568C; Fri, 2 Mar 2012 22:21:55 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 57E368FC08; Fri, 2 Mar 2012 22:21:55 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [96.47.65.170]) by cyrus.watson.org (Postfix) with ESMTPSA id 0A1A846B46; Fri, 2 Mar 2012 17:21:55 -0500 (EST) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 7F06DB922; Fri, 2 Mar 2012 17:21:54 -0500 (EST) From: John Baldwin To: Marius Strobl Date: Fri, 2 Mar 2012 17:18:37 -0500 User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p10; KDE/4.5.5; amd64; ; ) References: <201203022038.q22Kc5vd046376@svn.freebsd.org> <20120302214551.GB1635@alchemy.franken.de> In-Reply-To: <20120302214551.GB1635@alchemy.franken.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201203021718.38092.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Fri, 02 Mar 2012 17:21:54 -0500 (EST) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r232403 - in head/sys: dev/acpica dev/cardbus dev/pci powerpc/ofw sparc64/pci X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Mar 2012 22:21:55 -0000 On Friday, March 02, 2012 4:45:52 pm Marius Strobl wrote: > On Fri, Mar 02, 2012 at 08:38:05PM +0000, John Baldwin wrote: > > Author: jhb > > Date: Fri Mar 2 20:38:04 2012 > > New Revision: 232403 > > URL: http://svn.freebsd.org/changeset/base/232403 > > > > Log: > > - Add a bus_dma tag to each PCI bus that is a child of a Host-PCI bridge. > > The tag enforces a single restriction that all DMA transactions must not > > cross a 4GB boundary. Note that while this restriction technically only > > applies to PCI-express, this change applies it to all PCI devices as it > > is simpler to implement that way and errs on the side of caution. > > Hrm, wouldn't it have been more appropriate to implement this in the > Host-PCI bridges instead? Probably for anything but x86 this would > allow to easily distinguish at least between PCI and PCI-Express capable > bus hierarchies and would move the PAE workaround to the MD bits to > where it belongs. The PAE workaround is dying as I've already fixed HEAD to make boundary arguments use a bus_addr_t. However, I committed it in this fashion so it can be MFC'd since I can't merge the boundary KBI change. The reason I did not do this in the Host-PCI bridge drivers is that we would have to do this in umpteen different drivers, and all for a change that is mandated by the PCI spec and not specific to the various specs the Host-PCI bridge drivers all cater to (OFW, ACPI, MPTable, various and sundry embedded platforms, etc.). -- John Baldwin