From owner-freebsd-current Fri Jul 30 8:29:41 1999 Delivered-To: freebsd-current@freebsd.org Received: from janus.syracuse.net (janus.syracuse.net [205.232.47.15]) by hub.freebsd.org (Postfix) with ESMTP id DBF0014BE4 for ; Fri, 30 Jul 1999 08:29:36 -0700 (PDT) (envelope-from green@FreeBSD.org) Received: from localhost (green@localhost) by janus.syracuse.net (8.9.3/8.8.7) with ESMTP id LAA01457; Fri, 30 Jul 1999 11:28:38 -0400 (EDT) X-Authentication-Warning: janus.syracuse.net: green owned process doing -bs Date: Fri, 30 Jul 1999 11:28:35 -0400 (EDT) From: "Brian F. Feldman" X-Sender: green@janus.syracuse.net To: Mike Smith Cc: Stephen Hocking-Senior Programmer PGS Tensor Perth , current@FreeBSD.org Subject: Re: MTRR stuff In-Reply-To: <199907300934.CAA02191@dingo.cdrom.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Fri, 30 Jul 1999, Mike Smith wrote: > > For some video cards (to wit, the voodoo stuff), the MTRRs should be set up as > > follows > > > > write-combining > > +----------------------------------------------------------+ > > +-------+ > > uncacheable > > > > i.e. the two regions have the same starting area, but the small chunk for the > > registers should be uncacheable. When I try to do this using memconf on my > > K6-2, it spits the dummy. Is there a work around for this? > > The i686 MTRR implementation, at least, doesn't allow UC to overlap WC; > only Write-back and uncached are allowed to overlap. I don't know what > the K6's limitations are; you should talk to Brian Feldman about that. As long as a range isn't exactly the same (base, len being the same), it allows the change. The question is how does it fail? I let the hardware decide what to actually do with the registers, but I write them, so... I need to know where the problem is. > > -- > \\ The mind's the standard \\ Mike Smith > \\ of the man. \\ msmith@freebsd.org > \\ -- Joseph Merrick \\ msmith@cdrom.com > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message > Brian Fundakowski Feldman _ __ ___ ____ ___ ___ ___ green@FreeBSD.org _ __ ___ | _ ) __| \ FreeBSD: The Power to Serve! _ __ | _ \._ \ |) | http://www.FreeBSD.org/ _ |___/___/___/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message