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Subject: Re: [RFC/PATCH 4/7] Powerpc MSI implementation
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Russell King <rmk-pci@arm.linux.org.uk>
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Date: Wed, 08 Nov 2006 07:40:57 +1100
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Cc: Matthew Wilcox <matthew@wil.cx>, Greg Kroah-Hartman <greg@kroah.com>,
	linuxppc-dev@ozlabs.org, "Eric W.Biederman" <ebiederm@xmission.com>,
	linux-pci@atrey.karlin.mff.cuni.cz, "David S.Miller" <davem@davemloft.net>
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On Tue, 2006-11-07 at 20:14 +0000, Russell King wrote:
> On Tue, Nov 07, 2006 at 01:07:30PM -0700, Matthew Wilcox wrote:
> > On Tue, Nov 07, 2006 at 06:21:23PM +1100, Michael Ellerman wrote:
> > > We currently (ab)use the pci_dev to store our msi_info structure. We
> > > were hoping to stash it in the pci_dn, but that's not a goer, so the
> > > pci_dev seems like the right place, even though it seems naughty to
> > > bloat generic structs.
> > 
> > We have the per-irq void *chip_data; could this be the right place to
> > keep it instead?  That way, it won't take up space in the pci_dev for
> > devices which don't use MSI.
> 
> Bah.  chip_data is supposed to be __iomem.  I bet if you build ARM
> with sparse it'll kick out lots of warnings as a result of that loss.
> 
> Grumble, generic irq, pah.  Grumble.

Oh well... on various cases, on ppc, I use it not as __iomem but as a
pointer to a irq controller "instance" (which itself contains the
__iomem pointer, along with a bunch of other things).

But yeah, you were there first ;)

Ben.