From owner-freebsd-hackers Fri Jan 26 21:13:31 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from chopper.Poohsticks.ORG (chopper.poohsticks.org [63.227.60.73]) by hub.freebsd.org (Postfix) with ESMTP id 6850537B400 for ; Fri, 26 Jan 2001 21:13:14 -0800 (PST) Received: from chopper.Poohsticks.ORG (drew@localhost.poohsticks.org [127.0.0.1]) by chopper.Poohsticks.ORG (8.10.1/8.10.1) with ESMTP id f0R5D7h17509; Fri, 26 Jan 2001 22:13:11 -0700 Message-Id: <200101270513.f0R5D7h17509@chopper.Poohsticks.ORG> To: Richard Hodges Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: NEWBUS: multiple calls needed? In-reply-to: Your message of "Fri, 26 Jan 2001 18:02:50 PST." MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <17505.980572386.1@chopper.Poohsticks.ORG> Date: Fri, 26 Jan 2001 22:13:07 -0700 From: Drew Eckhardt Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message , rh@m atriplex.com writes: >I think I will just go ahead with allocating three separate resources >for them, but I would be very interested in other opinions. The different regions on a device often have different functionality which may allow/call for different memory access characteristics. For instance, you probably want attempts to write to onboard ROM to fault. You might mark to allow prefetch on large on-device buffers where reads have no side effects. Beyond that, if a specification does not prohibit a behavior eventually you'll run into a system that implements it because it seems to make sense or is just convienant. For example, if I thought about accomodating a systems where virtual and physical addresses matched (the Linux kernel used to do this), I might pad everything to page boundaries and skip a page between entries to make it easier to catch overruns. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message