Date: Fri, 26 Jan 2001 22:13:07 -0700 From: Drew Eckhardt <drew@PoohSticks.ORG> To: Richard Hodges <rh@matriplex.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: NEWBUS: multiple calls needed? Message-ID: <200101270513.f0R5D7h17509@chopper.Poohsticks.ORG> In-Reply-To: Your message of "Fri, 26 Jan 2001 18:02:50 PST." <Pine.BSF.4.10.10101261750060.31475-100000@mail.matriplex.com>
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In message <Pine.BSF.4.10.10101261750060.31475-100000@mail.matriplex.com>, 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
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