Re: [PATCH] Fix broken debug output reserve_region_with_split()

From: Benjamin Herrenschmidt
Date: Sun Oct 19 2008 - 23:38:19 EST

On Sat, 2008-10-18 at 08:45 +1100, Benjamin Herrenschmidt wrote:
> On Fri, 2008-10-17 at 14:11 -0700, Linus Torvalds wrote:
> > So the default is all the wrong way around. Make the defaults the sane
> > ones: 04x for IO, and 08x for MMIO, and then see if anybody wants anything
> > else. I seriously doubt they do. The whole ".. but but sparc" argument
> > seems to be entirely based on the total mis-conception of truncation that
> > has no relevance.
> Well, I definitely want 08x for IO on powerpc and I suspect anything
> non-x86 or alpha does as well... So I'm fine but I'd like to keep
> the default for IO at 08x unless you really have a strong opinion
> against it.

Actually, screw it. 04x is fine, as you said, it's not going to truncate
anyway. The reason I wanted 08x on powerpc is that we have legitimate
negative-looking values in there due to the way we do PIO on 32-bit and
we have most PCI IO looking like it's >64K on 64-but but that's no big
deal, ie, we don't actually need the padding for IO space.

So I'm happy with just a padding of 8 for memory which is even good
looking for most 64-bit archs in fact, and 4 for IO. I left the ability
for archs to pick a different value if they want to tho.

I'll send the patch separately after a test or two with a better mail


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