From owner-freebsd-current@FreeBSD.ORG  Wed Nov 12 09:56:36 2003
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
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 AE16C16A4CE; Wed, 12 Nov 2003 09:56:36 -0800 (PST)
Received: from regina.plastikos.com (216-107-106-250.wan.networktel.net
	[216.107.106.250])	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 6AD3643F75; Wed, 12 Nov 2003 09:56:35 -0800 (PST)
	(envelope-from fullermd@over-yonder.net)
Received: from mortis.over-yonder.net (adsl-212-172-144.jan.bellsouth.net
	[68.212.172.144])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by regina.plastikos.com (Postfix) with ESMTP
	id 15E0C6EECD; Wed, 12 Nov 2003 12:56:34 -0500 (EST)
Received: by mortis.over-yonder.net (Postfix, from userid 100)
	id B9B4320F26; Wed, 12 Nov 2003 11:56:31 -0600 (CST)
Date: Wed, 12 Nov 2003 11:56:31 -0600
From: "Matthew D. Fuller" <fullermd@over-yonder.net>
To: John Baldwin <jhb@FreeBSD.org>
Message-ID: <20031112175631.GQ12248@over-yonder.net>
References: <200311110220.10204@harrymail>
	<XFMail.20031111113526.jhb@FreeBSD.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <XFMail.20031111113526.jhb@FreeBSD.org>
User-Agent: Mutt/1.4.1i-fullermd.1
X-Editor: vi
X-OS: FreeBSD <http://www.freebsd.org/>
cc: current@FreeBSD.org
Subject: Re: APIC-UP related panic
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 12 Nov 2003 17:56:36 -0000

I, for one, am always pleased to see these sort of in-depth explanations
of these sort of shims.

On Tue, Nov 11, 2003 at 11:35:26AM -0500 I heard the voice of
John Baldwin, and lo! it spake thus:
> 
> It's documented in /sys/i386/conf/NOTES now along with 'device apic'.  For
> a longer explanation of what is happening:
>
[...]
> 
> So, by default, to work around motherboards that don't hook IRQ 0
> up to the I/O APIC, we route IRQ 0 through the the 8259A PICs.
>
[...]
>  
> However, if NO_MIXED_MODE works, that is actually the more desirable
> way to run your system.

How common is the need for this?  Does turning of mixed mode when it's
not needed give any real advantages higher up?


-- 
Matthew Fuller     (MF4839)   |  fullermd@over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/

"The only reason I'm burning my candle at both ends, is because I
      haven't figured out how to light the middle yet"