Subject: Re: [RFC PATCH] PCI-E broken on PPC (regression)

From: Matthew Wilcox <[email-masked]>
Date: Thu, 28 Jan 2010 20:45:24 -0700

On Wed, Jan 27, 2010 at 01:10:56PM +1100, Benjamin Herrenschmidt wrote:
> 
> > Cc'ing Ben for PPC.  Ben, should PPC use pci_scan_device when probing
> > its root busses?  Sounds like it just uses pci_device_add for each one
> > it finds instead?
> > 
> > If you don't actually need scanning (though what about hotplug?) we can
> > move the call to device_add instead...
> 
> Ok so I looked at the code and the problem goes way beyond root busses.
> 
> Basically, powerpc can use the code in arch/powerpc/kernel/pci_of_scan.c
> to "generate" the pci_dev without using config space probing or at least
> using as little of it as possible, using the firmware device-tree
> information instead.
> 
> This is also probably going to be moved to a more generic place and
> extended to be used optionally by other architectures.

Yes, having it under drivers/pci/ somewhere would be a big improvement,
that way we'd actually see it when trying to do cleanups and wouldn't
accidentally break your architectures.

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."