From owner-freebsd-hackers@FreeBSD.ORG Tue Mar 22 18:12:27 2011 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 3ACE31065670 for ; Tue, 22 Mar 2011 18:12:27 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id CB80F8FC1A for ; Tue, 22 Mar 2011 18:12:26 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id p2MICJ9d095200 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 22 Mar 2011 20:12:19 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id p2MICJhs019763; Tue, 22 Mar 2011 20:12:19 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id p2MICJd0019762; Tue, 22 Mar 2011 20:12:19 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 22 Mar 2011 20:12:19 +0200 From: Kostik Belousov To: Matthew Fleming Message-ID: <20110322181219.GU78089@deviant.kiev.zoral.com.ua> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="J7e1NV0wt6ySF7jo" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-3.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: freebsd-hackers Subject: Re: DMA controller on Northbridge? 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: Tue, 22 Mar 2011 18:12:27 -0000 --J7e1NV0wt6ySF7jo Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 22, 2011 at 10:11:04AM -0700, Matthew Fleming wrote: > How can I tell if the Northbridge on a machine has a built-in DMA > controller? And if it does, what device would I use to control it? >=20 > I ask because I'm working with a PCI card that has a 36-bit physical > address limit, and that means bounce buffers when using more than 64GB > of memory. I'd prefer not to use bounce buffers, and since the card's > memory that I'm using is mapped into the physical space of the FreeBSD > host, the entire address space of the card that I care about is > available to FreeBSD. So while pio to the card's memory is too slow > to be useful, if there was a way to use a DMA controller on the > motherboard to get data into and out of the card, that may be > preferable to using the card's DMAC with the limited address space. >=20 > But all that's just theory -- I have no idea how to tell whether the > mobo has a DMAC, and if it does, how to control it. Help? :-) >=20 > Attached is the boot dmesg; I can also run pciconf commands, etc., to > help out with figuring out what I have. I believe what are you looking for is ftp://download.intel.com/technology/.../Intel(r)_VT_for_Direct_IO.pdf On my X58 machine it is shown like this: none6@pci0:0:22:2: class=3D0x088000 card=3D0xf38015d9 chip=3D0x34328086 r= ev=3D0x12 hdr=3D0x00 vendor =3D 'Intel Corporation' device =3D 'DMA Engine' class =3D base peripheral cap 11[80] =3D MSI-X supports 1 message in map 0x10 cap 10[90] =3D PCI-Express 2 root endpoint max data 128(128) link x0(x0) cap 01[e0] =3D powerspec 3 supports D0 D3 current D0 --J7e1NV0wt6ySF7jo Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEARECAAYFAk2I5oMACgkQC3+MBN1Mb4gUeACeL42bSSf4wYnuIln1Coyq8gMK 24EAoLwk/hrrVsfObn91pUQpqlw9ZiSN =ux7n -----END PGP SIGNATURE----- --J7e1NV0wt6ySF7jo--