Re: [PATCH] sparse_irq aka dyn_irq v13

From: Benjamin Herrenschmidt
Date: Sun Nov 16 2008 - 23:27:36 EST


On Sun, 2008-11-16 at 16:26 -0800, H. Peter Anvin wrote:
> It would, however, be a good idea if IOAPICs had their numbers assigned
> at detection time, as opposed to when the interrupt is registered, thus
> making it a stable number for a single boot, at least. The same is
> probably true for MSI(-X); we could assign it a range of numbers when
> the device is enumerated (as opposed to when a driver is activated), but
> I don't know to what extent that is likely to cause more troubles than
> it solves.

On powerpc, we establish the mapping at PCI probe time so it's
reasonably stable. In fact, we even try to use virq == hwirq number if
the hwirq number fits and is available though I'm tempted to remove that
"feature" as it can make things more confusing in the end with some
interrupts having matching HW numbers and some not.

Cheers,
Ben.

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