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

[John Baldwin]

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.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org