Resource Allocation for Option Rom

Eric W. Biederman ebiederman at
Thu May 27 23:50:01 CEST 2004

Li-Ta Lo <ollie at> writes:

> On Thu, 2004-05-27 at 14:16, Eric W. Biederman wrote:
> > We could probably reserve a hole for this purpose, which
> > is a good idea except for bridges. 
> > 
> Can we just treat it as MEM resource and reuse the MEM resource
> allocation code ?

Yes that would be the easy way to reserver an area for the rom
to be enabled.  If the BAR is not large this should not be a problem.
> > Be very careful here.  The PCI spec allows the option rom BAR
> > to be mutually exclusive with the other BARS so in general
> > they both can not be enabled.
> > 
> Where is this stated in the spec ?

I saw it once long ago.  And the kernel avoids it.
But enabling just that BAR copying the data out,
and then reenabling the rest should not be a problem.


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