Re: multi-domain PCI and sysfs

David S. Miller
2004-09-08T04:15:33Z

On Tue, 7 Sep 2004 23:39:49 -0400
Jon Smirl <jonsmirl@gmail.com> wrote:

> On Tue, 7 Sep 2004 16:11:40 -0700, David S. Miller <davem@davemloft.net> wrote:
> > On Tue, 7 Sep 2004 18:58:53 -0400
> > Jon Smirl <jonsmirl@gmail.com> wrote:
> > > How many active VGA devices can I have in this system 1 or 4? If the
> > > answer is 4, how do I independently address each VGA card? If the
> > > answer is one, you can see why I want a pci0000 node to hold the
> > > attribute for turning it off and on.
> >
> > I don't know about the above but for a multi-domain system the
> > way it works is that the I/O ports are accessed using a different
> > base address for each domain.
>
> How does this work for IO ports in port space instead of memory mapped IO?

Those are IO ports in port space. IO ports and PCI memory space just
live in different physical memory windows, no special instructions
for IO port space access as on x86.