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

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.

cheers