Dear Jason Gunthorpe,

On Mon, 28 Jan 2013 15:51:05 -0700, Jason Gunthorpe wrote:

quoted

quoted

I'm refering to your earlier question about what PCI IDs to use for
the SW emulated devices. If there is no need for the host bridge then
you only need 1 PCI ID (for the root port bridge) and you can probably
fairly safely re-use the one in the Marvell config space of the HW.

Ah, ok, I see. But isn't a host bridge needed to bind all the
PCI-to-PCI bridges under a single bus, in order to get the global
resource assignment I was referring to?

The PCI-E spec requires it, but AFAIK it doesn't actually *do*
anything on Linux, and Linux doesn't require it.

I thought Thierry did this experiment and decided it wasn't necessary:

Could you detail what would be visible PCI bus topology if I remove the
emulated PCI host bridge? (And keeping one PCI-to-PCI bridge per PCIe
interface) ?

I'm just trying to understand what it would look like, in terms of
"lspci -t" output, because for now, it's not clear to me how everything
would fit together with the emulated host bridge.

Thanks,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com