From owner-freebsd-alpha Wed Oct 4 15:43:53 2000 Delivered-To: freebsd-alpha@freebsd.org Received: from anchor-post-33.mail.demon.net (anchor-post-33.mail.demon.net [194.217.242.91]) by hub.freebsd.org (Postfix) with ESMTP id 8CEA637B502 for ; Wed, 4 Oct 2000 15:43:51 -0700 (PDT) Received: from nlsys.demon.co.uk ([158.152.125.33] helo=herring.nlsystems.com) by anchor-post-33.mail.demon.net with esmtp (Exim 2.12 #1) id 13gxGP-00098k-0X; Wed, 4 Oct 2000 23:43:49 +0100 Received: from salmon.nlsystems.com (salmon.nlsystems.com [10.0.0.3]) by herring.nlsystems.com (8.9.3/8.8.8) with ESMTP id XAA14137; Wed, 4 Oct 2000 23:49:45 +0100 (BST) (envelope-from dfr@nlsystems.com) Date: Wed, 4 Oct 2000 23:43:16 +0100 (BST) From: Doug Rabson To: Wilko Bulte Cc: FreeBSD-alpha mailing list Subject: Re: max memory on Alpha? In-Reply-To: <20001003200741.A1318@freebie.demon.nl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Tue, 3 Oct 2000, Wilko Bulte wrote: > What is the currently max supported memory size on Alpha? 2Gb maybe? > Or will 4Gb also be OK? > > Reason for asking is that I want to try a AS8400 who is equipped > with 3x 4Gb memory module. Currently we are limited to 1Gb or 2Gb, depending on the platform. The tsunami driver uses a 2Gb window for dma and I think AS4x00 and AS8x00 also support 2Gb. Supporting more memory requires that all dma capable hardware is the busdma interface in its drivers. Given that, someone needs to write a small amount of code in busdma_machdep.c to either bounce transfers down to the 2Gb range or to use the sgmap to map the transfers into a reachable place. -- Doug Rabson Mail: dfr@nlsystems.com Phone: +44 20 8348 6160 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message