From owner-freebsd-doc Mon Dec 18 15:20:19 2000 From owner-freebsd-doc@FreeBSD.ORG Mon Dec 18 15:20:17 2000 Return-Path: Delivered-To: freebsd-doc@freebsd.org Received: from relay.ultimanet.com (relay.ultimanet.com [205.179.129.1]) by hub.freebsd.org (Postfix) with ESMTP id 5A5EA37B400 for ; Mon, 18 Dec 2000 15:20:17 -0800 (PST) Received: from Cloudfactory.ORG (cloudfactory.org [205.179.129.18]) by relay.ultimanet.com (8.9.3/8.9.3) with ESMTP id PAA15231 for ; Mon, 18 Dec 2000 15:38:57 -0800 Message-Id: <200012182338.PAA15231@relay.ultimanet.com> To: doc@FreeBSD.ORG Subject: Re: kernelconfig-config.html: ATA_ENABLE_ATAPI_DMA In-Reply-To: Message from Brooks Davis of "Mon, 18 Dec 2000 15:09:48 PST." <20001218150948.B10804@Odin.AC.HMC.Edu> Date: Mon, 18 Dec 2000 15:20:16 -0800 From: Randy Primeaux Sender: owner-freebsd-doc@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Brooks, Thank you for your quick response. I should have clarified that my local goal is to enable the "highest" transfer rate available, given my mixture of hardware and software. My global goal, is to see a comment for each option that alludes to "why, or why not, you would want to enable this option". I will ponder on your response, and see if I can come up with a politicly correct comment for the Handbook. I checked dmesg for my primary desktop and found: ata0-master: DMA limited to UDMA33, non-ATA66 compliant cable ad0: 29314MB [59560/16/63] at ata0-master UDMA33 ad1: 516MB [1988/14/38] at ata0-slave PIO3 ad2: 7665MB [15574/16/63] at ata1-master UDMA33 acd0: CDROM at ata1-slave using PIO3 I'll test tonight. Thanks. Brooks Davis writes: > On Mon, Dec 18, 2000 at 03:04:12PM -0800, Randy Primeaux wrote: > > The following entries are not clear to me, i.e. risk vs. benefit. > > I have UDMA33/66/100 devices, and am considering enabling > > ATA_ENABLE_ATAPI_DMA on a pci bus. > > Many stupid ATAPI devices (CD drives, ZIPs, etc) claim to support DMA, > but crash your system if you try to use it. Thus you can't turn this on > be default. It's worked for me on some systems, but there is no list > of working devices and it's unlikely that one will ever exist given that > CD drives are pretty much commodity devices and thus there's a lot of > junk out there. This doesn't belong in the handbook, IMO. If you can > suggest a better comment for the config file that wouldn't hurt, but > it's a very minor option. -- Randy Primeaux randy@cloudfactory.org tranze@hyperreal.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message