From owner-freebsd-hackers  Fri Aug 24 10:37: 4 2001
Delivered-To: freebsd-hackers@freebsd.org
Received: from freebsd.dk (fw-rl0.freebsd.dk [212.242.86.114])
	by hub.freebsd.org (Postfix) with ESMTP id 0C93E37B407
	for <freebsd-hackers@FreeBSD.ORG>; Fri, 24 Aug 2001 10:37:01 -0700 (PDT)
	(envelope-from sos@freebsd.dk)
Received: (from sos@localhost)
	by freebsd.dk (8.11.3/8.11.3) id f7OHbJI88588;
	Fri, 24 Aug 2001 19:37:19 +0200 (CEST)
	(envelope-from sos)
From: Søren Schmidt <sos@freebsd.dk>
Message-Id: <200108241737.f7OHbJI88588@freebsd.dk>
Subject: Re: ata0-master: non aligned DMA transfer attempted
In-Reply-To: <Pine.SOL.4.21.0108241119200.8160-100000@opal> "from Zhihui Zhang
 at Aug 24, 2001 11:24:27 am"
To: Zhihui Zhang <zzhang@cs.binghamton.edu>
Date: Fri, 24 Aug 2001 19:37:19 +0200 (CEST)
Cc: freebsd-hackers@FreeBSD.ORG
Reply-To: sos@freebsd.dk
X-Mailer: ELM [version 2.4ME+ PL88 (25)]
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=ISO-8859-1
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-hackers.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-hackers>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-hackers>
X-Loop: FreeBSD.ORG

It seems Zhihui Zhang wrote:
> 
> I write a program that writes into a raw device directly. Although the
> program runs OK, the system prints messages like:
> 
> ata0-master: non aligned DMA transfer attempted
> 
> What exactly happens here? Is there any problem in my program? 

You are probably trying to write an amount of data that is not
a whole number of the device's blocksize, for harddisks that
is 512bytes.

-Søren

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