Date: Tue, 27 Jan 2004 21:42:23 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: jhb@FreeBSD.org Cc: nate@root.org Subject: Re: cvs commit: src/share/man/man9 bus_alloc_resource.9 bus_set_resource.9 Message-ID: <20040127.214223.70221144.imp@bsdimp.com> In-Reply-To: <200401271528.31581.jhb@FreeBSD.org> References: <20040127.091238.05978307.imp@bsdimp.com> <20040127112940.W37323@root.org> <200401271528.31581.jhb@FreeBSD.org>
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In message: <200401271528.31581.jhb@FreeBSD.org>
John Baldwin <jhb@FreeBSD.org> writes:
: On Tuesday 27 January 2004 02:55 pm, Nate Lawson wrote:
: > On Tue, 27 Jan 2004, M. Warner Losh wrote:
: > > In message: <200401270604.i0R64Fpc076025@repoman.freebsd.org>
: > >
: > > Nate Lawson <njl@FreeBSD.org> writes:
: > > : njl 2004/01/26 22:04:15 PST
: > > :
: > > : FreeBSD src repository
: > > :
: > > : Modified files:
: > > : share/man/man9 bus_alloc_resource.9 bus_set_resource.9
: > > : Log:
: > > : Document my adventures in newbus land. Clarify some examples,
: > > : especially that count is in bytes, not bits. There are some drivers
: > > : that I think make this mistake. (I've seen counts of 16 in the tree).
: > >
: > > Counts of 16 in the tree are likely correct. Many devices have 8 or
: > > 16 or 32 io ports in ISA land. I've not seen any drivers make this
: > > mistake. Care to give an example?
: >
: > Well, for one ichsmb(4). It allocates 16 IO ports but only uses 8
: > according to its .h. The netgraph bt3c driver allocates 8 but only uses
: > 5. I'm curious if wi/owi really need 64 IO ports.
:
: The hardware needs to reserve any resource ranges that it will answer. Thus,
: the entire length of a PCI BAR needs to be reserved to keep another device
: from thinking it can use a resource that is silently going to conflict with
: another device.
Yes. This is even more important on ISA because there's no way to
know what those regs are, unlike PCI....
Warner
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