cvs commit: src/share/man/man9 bus_alloc_resource.9 bus_set_resource.9

[M. Warner Losh]

In message: <200401271528.31581.jhb at FreeBSD.org>
            John Baldwin <jhb at 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 at repoman.freebsd.org>
: > >
: > >             Nate Lawson <njl at 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