On Tue, 2009-11-17 at 23:39 +1100, Michael Ellerman wrote:

On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:

quoted

KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
it's not set, there are numerous small build errors. This is a small series
of patches to allow CONFIG_XICS to be unset in the config.

XICS appears to be some sort of interrupt controller but I'm not sure how
common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
universally requires CONFIG_XICS, the better path might be to force it to
be set.

It is indeed 'some sort of interrupt controller' :)

All the virtualised PSERIES systems have, or appear to have, a XICS. So
it's pretty common.

I think the only time you see an MPIC is on older machines, and even
then maybe only if you're running bare metal.

So it is pretty much required for a PSERIES kernel, but perhaps there
are cases where the BML guys want to be able to turn it off.

In fact this series makes me wonder whether we can drop support for a
single kernel image with pseries XICS & MPIC support.

If we could drop that requirement we could have a single set of names,
ie. API, for the irq routines and build either the XICS or MPIC
versions.

That would avoid all the code that needs a setup_foo_xics() and
setup_foo_mpic() - it'd just be setup_foo(), implemented by either the
XICS or MPIC code.

cheers