[Skiboot] [PATCH v2] phb4: Enable PCI peer-to-peer

[Benjamin Herrenschmidt]

On Sun, 2017-07-16 at 15:04 -0500, Frederic Barrat wrote:
> 
> Thanks, Ben
> 
> Intermediate switches... I'm getting more than I bargained for here.
> 
> The pressing need we have for p2p doesn't involve a setup with 2 devices 
> under the same PHB, so I'm thinking maybe I should skip it for now, but 
> I'd like to at least understand what would be required. google tells me 
> I need to find a pci spec about ACS, is that right? Do you have it? Am I 
> entering a world of pain?

I'm not sure :-) For now, I'd just return an error from skiboot and we
can make it a Linux problem I suppose. We may want to look at the PLX
spec see if they have something specific, but something like that is
probably better dealt at the generic linux level. Keep an eye on what
those other guys were proposing...

Cheers,
Ben.