From owner-p4-projects@FreeBSD.ORG Mon Apr 25 06:38:22 2005 Return-Path: Delivered-To: p4-projects@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 32767) id 0E20D16A4D0; Mon, 25 Apr 2005 06:38:22 +0000 (GMT) Delivered-To: perforce@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A582D16A4CE; Mon, 25 Apr 2005 06:38:21 +0000 (GMT) Received: from schizoid.village.org (schizoid.village.org [168.103.84.176]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0B3A343D2F; Mon, 25 Apr 2005 06:38:21 +0000 (GMT) (envelope-from imp@bsdimp.com) Received: from localhost (duck-pond.village.org [10.200.4.2]) j3P6cKVY010498; Mon, 25 Apr 2005 00:38:20 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Mon, 25 Apr 2005 00:37:57 -0600 (MDT) Message-Id: <20050425.003757.74682881.imp@bsdimp.com> To: marcel@xcllnt.net From: "M. Warner Losh" In-Reply-To: References: <200504250459.j3P4xWxs057683@repoman.freebsd.org> <20050424.234915.41699183.imp@bsdimp.com> X-Mailer: Mew version 2.2 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: marcel@freebsd.org cc: perforce@freebsd.org Subject: Re: PERFORCE change 75921 for review X-BeenThere: p4-projects@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: p4 projects tree changes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Apr 2005 06:38:22 -0000 In message: Marcel Moolenaar writes: : : On Apr 24, 2005, at 10:49 PM, M. Warner Losh wrote: : : > In message: <200504250459.j3P4xWxs057683@repoman.freebsd.org> : > Marcel Moolenaar writes: : > : http://perforce.freebsd.org/chv.cgi?CH=75921 : > : : > : Change 75921 by marcel@marcel_nfs on 2005/04/25 04:59:01 : > : : > : Allow VGA resources across PCI-PCI bridges. Required to : > : support a PCI based VGA driver with the VGA hardware : > : behind a PCI-PCI bridge. : > : > WE need to make sure that the ISA bit and VGA bits are set properly on : > those bridges with vga children and peers of bridges with vga : > children before allowing this... : : Ideally, yes. But since only one PCI device of class display and : subclass VGA can have the legacy VGA addresses enabled and we're : not mucking with the system configuration in that respect, we're : not really doing anything dangerous by allowing the VGA addresses : without such scrutiny provided we don't try to allocate those : addresses for any ol' VGA display device that we find on the PCI : busses in the system. Actually yes, really, we need to do this. Most system BIOSes will get it right, but not all. We'll likely need to cope with them when we turn this on. MS has an excellent paper on this topic. That paper seems to imply that one can have multiple VGA devices in a system behind different bridges. I guess what I'm saying here is that we'll need to be careful and chances are good we'll have some people that have issues which didn't before. Warner