Date: Mon, 25 Aug 2003 18:51:20 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: jhb@FreeBSD.org Cc: marcel@xcllnt.net Subject: Re: PERFORCE change 36551 for review Message-ID: <20030825.185120.42774461.imp@bsdimp.com> In-Reply-To: <XFMail.20030825170230.jhb@FreeBSD.org> References: <20030822.154941.31253895.imp@bsdimp.com> <XFMail.20030825170230.jhb@FreeBSD.org>
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In message: <XFMail.20030825170230.jhb@FreeBSD.org>
John Baldwin <jhb@FreeBSD.org> writes:
:
: On 22-Aug-2003 M. Warner Losh wrote:
: > In message: <20030822173606.GA849@dhcp42.pn.xcllnt.net>
: > Marcel Moolenaar <marcel@xcllnt.net> writes:
: >: > > So, please. Do not blur the distinction by having it all mapped as
: >: > > ISA devices. I really don't want to have to shoot you :-)
: >: >
: >: > Well, the other alternative is to add an ACPI attachment for every
: >: > ISA device. I'm sure you can appreciate my lack of zeal for this
: >: > option. :(
: >:
: >: Moving forward I would think that you replace ISA bus attachments
: >: with ACPI bus attachments until such time you don't have any ISA
: >: drivers anymore. That is, you probably need drivers for ISA devices
: >: that exist on alpha, so you'll end up with a handful of drivers
: >: that have both ACPI and ISA. Hmmm, I don't know if this holds for
: >: pc98 or not?
: >
: > Assumption: bus attachement are cheap.
: >
: > There will be a number of drivers that violate this, and may need to
: > be rearranged, but forcing a device onto the ISA bus because we don't
: > have a ACPI attachment for it is lame.
: >
: > The pc98 folks have expressed a strong desire that CBUS front ends be
: > separate from ISA front ends. There's a number of technical reasons
: > for this, in addition to the asthetic argument. Basically, they've
: > shoe-horned cbus into ISA bus, and it is a poor fit. Let's learn from
: > that lesson.
:
: ACPI isn't a bus like c-bus though. ACPI enumerates ISA devices.
: A closer analogy would be to create a pnpbios0 bus for ISA devices
: enumerated by the PNP BIOS.
cbus and ebus are more closely related. But cbus also has an
enumeration. It also sounds like acpi enumerates devices at addresses
that may or may not be completely isa.
Warner
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