From owner-freebsd-current  Mon Mar 24 23:30:17 2003
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 18B2437B40F
	for <freebsd-current@FreeBSD.ORG>; Mon, 24 Mar 2003 23:29:55 -0800 (PST)
Received: from spider.deepcore.dk (cpe.atm2-0-56339.0x50c6aa0a.abnxx2.customer.tele.dk [80.198.170.10])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 3EFFD4415A
	for <freebsd-current@FreeBSD.ORG>; Mon, 24 Mar 2003 23:16:50 -0800 (PST)
	(envelope-from sos@spider.deepcore.dk)
Received: (from sos@localhost)
	by spider.deepcore.dk (8.12.8/8.12.8) id h2P7GSXe047117;
	Tue, 25 Mar 2003 08:16:28 +0100 (CET)
	(envelope-from sos)
From: Soeren Schmidt <sos@spider.deepcore.dk>
Message-Id: <200303250716.h2P7GSXe047117@spider.deepcore.dk>
Subject: Re: Broken DMA devices
In-Reply-To: <20030324195958.GB681@lenny.anarcat.ath.cx>
To: The Anarcat <anarcat@anarcat.ath.cx>
Date: Tue, 25 Mar 2003 08:16:28 +0100 (CET)
Cc: Kevin Oberman <oberman@es.net>, Don <don@calis.blacksun.org>,
	Craig Reyenga <creyenga@connectmail.carleton.ca>,
	freebsd-current@FreeBSD.ORG
X-Mailer: ELM [version 2.4ME+ PL98b (25)]
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=ISO-8859-1
X-Spam-Status: No, hits=-19.5 required=5.0
	tests=EMAIL_ATTRIBUTION,IN_REP_TO,QUOTED_EMAIL_TEXT,
	      REPLY_WITH_QUOTES
	autolearn=ham	version=2.50
X-Spam-Level: 
X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp)
Sender: owner-freebsd-current@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-current.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-current>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-current>
X-Loop: FreeBSD.ORG

It seems The Anarcat wrote:
> > hw.ata.atapi_dma="1"    # Run the CD-ROM/DVD in DMA mode
> > to /boot/loader.conf.
> > 
> > This should be in almost EVERY /boot/loader.conf. The default is 0 (PIO)
> > because DMA is broken on at least a few early CD readers, but it is
> > very rare to have it fail. (I've never seen it.)
> 
> Can't the ata drivers detect that condition or recognize the set of
> drives that are broken instead of penalizing everyone else?

ATAPI DMA is more likely to be broken than to be working, it is a 
function of both controller chip and device, in some situations even
a function of what master/slave device combo we have..

There is a reason that almost all OS's out there has it disabled as default :)

-Søren

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message