[PATCH 2/7] Powerpc MSI implementation

[Benjamin Herrenschmidt]

On Fri, 2007-01-12 at 08:20 +1100, Benjamin Herrenschmidt wrote:
> > So, no, I don't agree with this implementation and don't want to see it
> > go through anyone's tree into mainline just yet.
> 
> So why, when we posted it earlier, you said the exact opposite ? That
> you actually liked it and wanted to see it as a replacement of the
> current cruft ?
> 
> That's been the logic from day one. We implement a generic MSI support
> that supports multiple backends, we do it as a powerpc version at first
> since that's what we can actively test and provide backends for, then as
> a second step, we work with the intel folks to port their stuff over to
> our implementation and replace the current crappy generic one.

/me calms down a bit ... :-)

Ok, so what about we do:

 - Move that new implementation to drivers/pci
 - Have a CONFIG_NEW_MSI or something like that to select between
the old and the new implementation
 - Have the change to pci_dev be based on that config option

Note: There should be no impact on drivers nor anything out of
drivers/pci and associated arch support code, the API exposed to drivers
should be identical.

That way, it will be easier for Intel/Altix folks to port over to the
new code as it will be accessible to all archs via a config option. Once
Intel & Altix have ported over, the old code can be removed and
CONFIG_NEW_MSI too.

I know that other archs have actually been waiting for that new
infrastructure (well, according to some feedback we got when Michael
first posted it) so that's probably a better approach than having it in
arch/powerpc indeed.

Cheers,
Ben.