From owner-freebsd-ppc@FreeBSD.ORG  Wed Oct 22 18:05:06 2008
Return-Path: <owner-freebsd-ppc@FreeBSD.ORG>
Delivered-To: freebsd-ppc@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 26D20106567B;
	Wed, 22 Oct 2008 18:05:06 +0000 (UTC)
	(envelope-from grehan@freebsd.org)
Received: from alto.onthenet.com.au (alto.OntheNet.com.au [203.13.68.12])
	by mx1.freebsd.org (Postfix) with ESMTP id DDCE08FC2C;
	Wed, 22 Oct 2008 18:05:05 +0000 (UTC)
	(envelope-from grehan@freebsd.org)
Received: from dommail.onthenet.com.au (dommail.OntheNet.com.au [203.13.70.57])
	by alto.onthenet.com.au (Postfix) with ESMTP id DA532117B6;
	Thu, 23 Oct 2008 04:05:03 +1000 (EST)
Received: (from dommail.onthenet.com.au [192.100.104.17])
	by dommail.onthenet.com.au (MOS 3.8.6-GA)
	with HTTP/1.1 id EKQ11018 (AUTH peterg@ptree32.com.au);
	Thu, 23 Oct 2008 04:04:22 +1000 (EST)
From: Peter Grehan <grehan@freebsd.org>
To: Nathan Whitehorn <nwhitehorn@freebsd.org>
X-Mailer: Mirapoint Webmail Direct 3.8.6-GA
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-Id: <20081023040422.EKQ11018@dommail.onthenet.com.au>
Date: Thu, 23 Oct 2008 04:04:22 +1000 (EST)
X-Mailman-Approved-At: Wed, 22 Oct 2008 20:09:28 +0000
Cc: freebsd-ppc@freebsd.org
Subject: Re: graphics on G4
X-BeenThere: freebsd-ppc@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Porting FreeBSD to the PowerPC <freebsd-ppc.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-ppc>,
	<mailto:freebsd-ppc-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-ppc>
List-Post: <mailto:freebsd-ppc@freebsd.org>
List-Help: <mailto:freebsd-ppc-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-ppc>,
	<mailto:freebsd-ppc-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 22 Oct 2008 18:05:06 -0000

Hi Nathan,

>One thing that worries me about our PMAP layer could cause
>this. This machine has a lot of RAM. What happens if we have
>physical or device memory in the same range as kmem VAs?
>It seems like trying to modify it through the BAT map (as
>zero/copy page, /dev/mem and friends do) will overwrite
>random bits of KVA instead...

 Apple h/w seems to use 0-2G for RAM, and 2G and up for MMIO.
G5's can then use > 4G for additional RAM. I've not seen a
system that has a conflict with the 2 seg's used for KVA, but
I wouldn't say it's not possible.
 
 Justin - can you drop into OFW, do a 'dev screen' and
'.properties', and list the 'address' property ?

later,

Peter.