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Date: Sun, 3 Oct 2010 20:34:29 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: "Eric W. Biederman" <ebiederm@xmission.com>
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        Jesse Barnes <jbarnes@virtuousgeek.org>,
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        Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [patch 46/47] powerpc: Use new irq allocator
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On Sun, 3 Oct 2010, Eric W. Biederman wrote:

> Thomas Gleixner <tglx@linutronix.de> writes:
> 
> >> That would make things much cleaner and in fact move one large step
> >> toward being able to make powerpc virq scheme generic, which seems to be
> >> a good idea from what I've heard :-)
> >
> > Yep.
> 
> I'm not certain about making the ppc virq scheme generic.  Maybe it is
> just my distorted impression but I have the understanding that ppc irq
> numbers mean nothing and are totally unstable whereas on x86 irq numbers
> in general are stable (across kernel upgrades and changes in device
> probe order) and the irq number has a useful hardware meaning.  Which
> means you don't have to go through several layers of translation tables
> to figure out which hardware pin you are talking about.

Nobody is forced to use it, but we have already several instances of
virq mapping implementations in arch/*. Having a generic
infrastructure for this makes a ton of sense.

Thanks,

	tglx