From owner-freebsd-current Thu Apr 4 18: 4:14 2002 Delivered-To: freebsd-current@freebsd.org Received: from hawk.mail.pas.earthlink.net (hawk.mail.pas.earthlink.net [207.217.120.22]) by hub.freebsd.org (Postfix) with ESMTP id C378537B41A; Thu, 4 Apr 2002 18:04:08 -0800 (PST) Received: from pool0517.cvx21-bradley.dialup.earthlink.net ([209.179.194.7] helo=mindspring.com) by hawk.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 16tJ5B-0001Z5-00; Thu, 04 Apr 2002 18:04:06 -0800 Message-ID: <3CAD05FD.4FE5B863@mindspring.com> Date: Thu, 04 Apr 2002 18:03:41 -0800 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: mjacob@feral.com Cc: Andrew Gallatin , freebsd-current@freebsd.org, gibbs@freebsd.org Subject: Re: BUS_SPACE_MAXSIZE & isp driver. References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Matthew Jacob wrote: > Neither is really applicable here. The actual limits for alpha depend on the > platforma and how you implement it. Typically, the bigger alphas have been > implemented with a 2GB direct mapped window, and then, if they have it, a S/G > map setup for the rest (if any) of memory, which also can include ISA mapping. Thanks for the clarification. I was confusing BUS_SPACE_MAXSIZE with BUS_SPACE_MAXSIZE_24BIT and BUS_SPACE_MAXSIZE_32BIT. It's probably too late to rename BUS_SPACE_MAXSIZE to something like BUS_SPACE_MAXXFER. 8-(. > The current Alpha 2.4.18 Linux implementation is quite happy to DMA to > 4GB > on quite a few alphas. Ah. Reference code. > BUS_SPACE_MAXSIZE seems to be related to the 'largest xfer you will be allowed > to do at one time'- which is wrong because MAXPHYS is larger. Yeah, I get that now. No need to beat me up, I can take care of it myself. 8-) 8-). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message