PCI IO range limitation

Benjamin Herrenschmidt benh at kernel.crashing.org
Tue Jul 3 21:13:30 EST 2007


On Tue, 2007-07-03 at 11:24 +0200, Marian Balakowicz wrote:
> Benjamin Herrenschmidt wrote:
> > On Thu, 2007-06-28 at 12:20 +0200, Marian Balakowicz wrote:
> >> I guess that with the above dropping of non-zero based PCI IO ranges
> >> this is not supposed to be working. But does anyone know why?
> > 
> > We just fixed that for 64 bits but 32 bits still has the limitation.
> > Note that it's not a very good idea to have your IO range at !0 if
> > you're going to use anything ISA-like, such as a VGA video card or other
> > legacy devices behind a PCI southbridge or SuperIO.
> 
> Agree with the zero-based IO range for ISA devices. But, knowing we don't
> have any ISA stuff on board it should be possible to change the IO base.

And you don't plan to ever have a VGA video card ?

> Are you planning on modifications for 32 bits as well?

Not right now, but you are welcome to send a patch :-) Though I fail to
see why you want to do it.

Ben





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