Re: PCI domains

[Simon Burge <simonb%NetBSD.org@localhost>]

"Christoph Egger" wrote:

> > "Christoph Egger" wrote:
> > 
> > > PCI domains are part of the PCI host bridge specification.
> > > It is a 16bit-wide number.
> > 
> > Can you please provide a reference for this?  There's nothing mentioned
> > in the PCI Local Bus Specification version 2.3.  I can find plenty of
> > references to "clock domains" and "address space domains", but when I
> > exclude Linux references I can't seem to find anything useful.
> 
> It's not in the PCI Local Bus Specification nor in the
> PCI-to-PCI Bridge Specification. It is in the
> PCI Host Bridge Specification which is a vendor specific paper.

Again, can you please point to a specific reference?  I grabbed a few
different host bridge specs and have yet to find any concrete reference
to "PCI domains".

> The pci host bridges for the alpha port implements PCI domains.

Our alpha port?

thoreau 1170> grep -ir domain alpha
alpha/include/ieeefp.h: * Public domain.
alpha/include/fpu.h: * the definition prefix can easily be determined from 
public domain
alpha/pci/pci_6600.h:/* Public Domain */

> > Everything I see so far says that a "PCI domain" is an OS abstraction
> > and not part of a PCI specification.  I'm also not sure exactly what
> > problem you're trying to solve - why exactly does it matter if two PCI
> > busses share a common "domain" or not?
> 
> Read the C comment in my first mail. X.org wants to have some
> information NetBSD currently doesn't provide to userland.
> This is what I rather want to discuss.

Is that the comment that starts "With each /dev/pci* we can map
everything on the same root"?  I'll have to re-read that again to make
sure I understand what you're saying, but in a nutshell is the reason
you want to introduce the "PCI domains" concept to keep Xorg happy?

Cheers,
Simon.