From owner-freebsd-hackers@FreeBSD.ORG Wed Aug 13 16:00:26 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CD98E37B401 for ; Wed, 13 Aug 2003 16:00:26 -0700 (PDT) Received: from odin.ac.hmc.edu (Odin.AC.HMC.Edu [134.173.32.75]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0AC4343FBD for ; Wed, 13 Aug 2003 16:00:26 -0700 (PDT) (envelope-from brdavis@odin.ac.hmc.edu) Received: from odin.ac.hmc.edu (IDENT:brdavis@localhost.localdomain [127.0.0.1]) by odin.ac.hmc.edu (8.12.9/8.12.3) with ESMTP id h7DN0M7c029562; Wed, 13 Aug 2003 16:00:22 -0700 Received: (from brdavis@localhost) by odin.ac.hmc.edu (8.12.9/8.12.3/Submit) id h7DN0MGK029561; Wed, 13 Aug 2003 16:00:22 -0700 Date: Wed, 13 Aug 2003 16:00:22 -0700 From: Brooks Davis To: Alexander Serkov Message-ID: <20030813230022.GA28561@Odin.AC.HMC.Edu> References: <200308140145.45882.serkov@ukrpost.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9amGYk9869ThD9tj" Content-Disposition: inline In-Reply-To: <200308140145.45882.serkov@ukrpost.net> User-Agent: Mutt/1.5.4i X-Virus-Scanned: by amavisd-milter (http://amavis.org/) on odin.ac.hmc.edu cc: freebsd-hackers@freebsd.org Subject: Re: Why is ATAPI DMA disabled by default ? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Aug 2003 23:00:27 -0000 --9amGYk9869ThD9tj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Aug 14, 2003 at 01:45:45AM +0300, Alexander Serkov wrote: > I use 5.1-current and have found that by default FreeBSD disables ATAPI's= =20 > support for DMA transfers and thus uses CPU hungry PIO modes. > It even makes sysctl used to change this read-only. > I had changed the default value of atapi_dma to 1 in dev/ata/atapi-all.c = to 1=20 > and it worked fine for me. > Can someone explain why it is disabled? Lots of drives, even fairly new ones be well know vendors, hang the system during boot if ATAPI DMA is enabled because they lie about supporting it. -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --9amGYk9869ThD9tj Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE/OsMFXY6L6fI4GtQRAjQLAJ9CCOm6ZYyPPGqSoznZxVCcdXql9QCgpXm2 gZ6h4jUTP6nSCciUYuZ/0lE= =CB9/ -----END PGP SIGNATURE----- --9amGYk9869ThD9tj--