From owner-freebsd-current Thu Apr 4 18: 8: 3 2002 Delivered-To: freebsd-current@freebsd.org Received: from beppo.feral.com (beppo.feral.com [192.67.166.79]) by hub.freebsd.org (Postfix) with ESMTP id 84E3137B434; Thu, 4 Apr 2002 18:07:49 -0800 (PST) Received: from mailhost.feral.com (mjacob@mailhost.feral.com [192.67.166.1]) by beppo.feral.com (8.11.3/8.11.3) with ESMTP id g3527kf83143; Thu, 4 Apr 2002 18:07:46 -0800 (PST) (envelope-from mjacob@feral.com) Date: Thu, 4 Apr 2002 18:07:46 -0800 (PST) From: Matthew Jacob X-Sender: mjacob@beppo Reply-To: mjacob@feral.com To: Terry Lambert Cc: Andrew Gallatin , freebsd-current@freebsd.org, gibbs@freebsd.org Subject: Re: BUS_SPACE_MAXSIZE & isp driver. In-Reply-To: <3CAD05FD.4FE5B863@mindspring.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 On Thu, 4 Apr 2002, Terry Lambert wrote: > 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-(. Yes. If we've understood it at all. There are no documents really describing it. > > > > 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-). No, no.... at least you showed some interest :-) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message