Re: Non-page-aligned PCI base address

Gerard Roudier (groudier@club-internet.fr)
Thu, 26 Nov 1998 23:16:17 +0100 (MET)


On Thu, 26 Nov 1998, Martin Mares wrote:

> Hello,
>
> > Are you sure of your statement?
> >
> > The preferred IO method for PCI is MMIO. Normal IO exists because of Intel
> > compatibility. PCI boards that donnot support MMIO are just shit because
> > they donnot take advantage of PCI posted writes.
>
> I didn't say MMIO is rare, I've only said that cards with less than 4KB
> of MMIO are relatively rare.

They aren't rare, in my opinion. IO registers generally donnot need a so
large space and are accessible from both IO space and MMIO space. The MMIO
space is _not_ prefetchable. Frame buffers that are prefetchable are
different things. So, probably _most_ of PCI boards have probably some
MMIO space (_not_ prefetchable) smaller that 4K. That's just the opposite
of rare.

Regards,
Gerard.

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