Re: [PATCH] sparse_irq aka dyn_irq v13

From: Benjamin Herrenschmidt
Date: Sun Nov 16 2008 - 23:23:12 EST


On Sun, 2008-11-16 at 15:48 -0800, H. Peter Anvin wrote:
> Yinghai Lu wrote:
> > 2. make irq number is bus/devfn/idx, and every dev func will use 12bit range, irq number is relatively fixed not like current MSI irq creating is some kind of floating from NR_IRQS too.
>
> 2 is *STILL WRONG*, dammit!
>
> You keep bringing this one up, but our PCI addressing is
> *DOMAIN*/bus/devfn -- it falls flat on its face when you have more than
> 16 PCI domains. CAN WE PLEASE STOP WITH THIS FOOLISHNESS NOW!

Besides, the relationship between PCI location and IRQ numbers seems to
be an x86 thingy ... don't bring that into the generic code please !

IRQ numbers are arbitrary, some platforms make up numbers out of the
blue, or they can be hypervisor internal tokens etc...

The only sane way to handle this generically IMHO is to do what we do
on powerpc (and I think sparc64) which is to totally disconnect the HW
number from the "linux" number.

Ben.


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