From owner-freebsd-hardware@FreeBSD.ORG  Sun Aug  9 14:15:52 2009
Return-Path: <owner-freebsd-hardware@FreeBSD.ORG>
Delivered-To: freebsd-hardware@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 822E8106566B;
	Sun,  9 Aug 2009 14:15:52 +0000 (UTC) (envelope-from mav@FreeBSD.org)
Received: from cmail.optima.ua (cmail.optima.ua [195.248.191.121])
	by mx1.freebsd.org (Postfix) with ESMTP id D0B048FC19;
	Sun,  9 Aug 2009 14:15:51 +0000 (UTC)
Received: from [212.86.226.226] (account mav@alkar.net HELO
	mavbook.mavhome.dp.ua)
	by cmail.optima.ua (CommuniGate Pro SMTP 5.2.9)
	with ESMTPSA id 251066089; Sun, 09 Aug 2009 17:15:48 +0300
Message-ID: <4A7ED9DF.1080007@FreeBSD.org>
Date: Sun, 09 Aug 2009 17:14:55 +0300
From: Alexander Motin <mav@FreeBSD.org>
User-Agent: Thunderbird 2.0.0.21 (X11/20090405)
MIME-Version: 1.0
To: Ed Schouten <ed@80386.nl>
References: <4A7DF076.4070203@FreeBSD.org>
	<20090809.202549.27838630.nyan@jp.FreeBSD.org>
	<20090809134724.GX1292@hoeg.nl>
In-Reply-To: <20090809134724.GX1292@hoeg.nl>
Content-Type: text/plain; charset=KOI8-R; format=flowed
Content-Transfer-Encoding: 7bit
Cc: freebsd-hardware@freebsd.org, Takahashi Yoshihiro <nyan@jp.FreeBSD.org>,
	freebsd-arch@freebsd.org
Subject: Re: Do we still need ATA disk CHS addressing?
X-BeenThere: freebsd-hardware@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: General discussion of FreeBSD hardware <freebsd-hardware.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hardware>, 
	<mailto:freebsd-hardware-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hardware>
List-Post: <mailto:freebsd-hardware@freebsd.org>
List-Help: <mailto:freebsd-hardware-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hardware>, 
	<mailto:freebsd-hardware-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 09 Aug 2009 14:15:52 -0000

Ed Schouten wrote:
> * Takahashi Yoshihiro <nyan@jp.FreeBSD.org> wrote:
>> In article <4A7DF076.4070203@FreeBSD.org>
>> Alexander Motin <mav@freebsd.org> writes:
>>> While preparing wrapping ATA(4) low-level drivers code into CAM SIM, I
>>> would like to remove CHS addressing support to make code cleaner. CHS
>>> addressing is officially declared obsoleted and replaced by LBA. Since
>>> ATA/ATAPI-6 specification (October 2001) it is even no longer
>>> documented.
>>>
>>> Have anybody seen ATA drive without LBA support in last years?
>>> Any other objections against removing it?
>> PC98 uses CHS addressing because the internal interface works for very
>> old HDD only, so I hope it remains if possible.  But if you need a lot
>> of works for CHS support, I agree to remove it.
> 
> Wouldn't it be possible to keep the old ATA code in the tree for users
> who want to use stuff like this?

I am going to make it switchable via kernel option, until new code 
completely settle. It should be possible to keep CHS support in this 
legacy mode.

-- 
Alexander Motin