From owner-freebsd-alpha@FreeBSD.ORG Wed Nov 5 06:23:54 2003 Return-Path: Delivered-To: freebsd-alpha@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CCD2616A4CE for ; Wed, 5 Nov 2003 06:23:54 -0800 (PST) Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id AA89243FBD for ; Wed, 5 Nov 2003 06:23:53 -0800 (PST) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.12.10/8.12.10) with ESMTP id hA5ENqJY000186 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Wed, 5 Nov 2003 09:23:53 -0500 (EST) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.6/8.9.1) id hA5ENl578380; Wed, 5 Nov 2003 09:23:47 -0500 (EST) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16297.2035.310311.968335@grasshopper.cs.duke.edu> Date: Wed, 5 Nov 2003 09:23:47 -0500 (EST) To: Fred Clift In-Reply-To: <20031104155314.W3281@irfcn.qzm.berz.irevb.arg> References: <20031102022925.W28113@loafier.com> <20031104155314.W3281@irfcn.qzm.berz.irevb.arg> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid cc: freebsd-alpha@freebsd.org Subject: Re: Miata MX5 and 64 bit gigabit ethernet X-BeenThere: freebsd-alpha@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Porting FreeBSD to the Alpha List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Nov 2003 14:23:54 -0000 Fred Clift writes: > If the card does dma, then it will be unlikley to work. I dont know that > Gigabit ethernet existed when miatas were new, and hence, DEC wouldn't Please get a clue or stop spreading FUD. The DMA bug occurs when crossing a page (8K) boundary using scatter/gather DMA READs. FreeBSD doesn't even use scatter/gather for anything but ISA cards at the moment. Most GigE cards are not ISA ;) For what its worth, we used Alteon Tigon II Gigabit nics on our Miatas back when the hardware was current and 4.0 was -CURRENT. Even if it works, don't expect great performance. As best as I can remember, we never managed to get much more than 500Mb/sec throughput, even with jumbo frames. This is partly because the Miata's PCI bus / memory system really sucks by modern standards and it can't get anywhere near the 250MB/sec theoretical PCI max... Drew