From owner-freebsd-hackers@FreeBSD.ORG  Tue Aug 19 16:39:40 2003
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
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 55A1B16A4C0; Tue, 19 Aug 2003 16:39:40 -0700 (PDT)
Received: from artax.karlin.mff.cuni.cz (artax.karlin.mff.cuni.cz
	[195.113.31.125])	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 77D8B43FBD; Tue, 19 Aug 2003 16:39:39 -0700 (PDT)
	(envelope-from mikulas@artax.karlin.mff.cuni.cz)
Received: by artax.karlin.mff.cuni.cz (Postfix, from userid 17421)
	id 79FFC3FAC; Wed, 20 Aug 2003 01:39:37 +0200 (CEST)
Received: from localhost (localhost [127.0.0.1])
	by artax.karlin.mff.cuni.cz (Postfix) with ESMTP
	id 7827B2FBD9; Wed, 20 Aug 2003 01:39:37 +0200 (CEST)
Date: Wed, 20 Aug 2003 01:39:37 +0200 (CEST)
From: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
To: sos@FreeBSD.org
Message-ID: <Pine.LNX.4.44.0308200130120.12189-100000@artax.karlin.mff.cuni.cz>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: freebsd-hackers@freebsd.org
Subject: Bug FreeBSD 4.8 ATA driver
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 19 Aug 2003 23:39:40 -0000

Hi

I am reading FreeBSD ATA drivers because I want to use them as base for my
ATA driver and I found a total nonsence: in ata-dma.c in FreeBSD 4.8,
there is line

if (!((pci_read_config(parent,0x40,4)>>(ch->unit<<8))&0x4000)) {

if ch->unit is 1, config word is shifted by 256 bytes, which gives
undefined result in C. How was this meant? What should it do?

Mikulas