Re: [patch] x86 supports NO_IRQ convention

From: Alan Cox
Date: Mon Jun 23 2008 - 05:26:31 EST


On Sun, 22 Jun 2008 19:53:18 -0700
David Brownell <david-b@xxxxxxxxxxx> wrote:

> Hmm, x86 doesn't seem to support the NO_IRQ convention. This means
> that portable code can't use it. Which in turn means that there's
> no portable way for drivers to know whether they have been handed a
> valid IRQ number (zero usually being valid). Double-plus ungood.

NAK. It was discussed before repeatedly as you suspected and settled by
Linus ultimately.

Zero is not a valid IRQ in the kernel mapping of things. If you have a
physical IRQ 0 remap it. That way you can write the more natural

if (dev->irq)
setup_for_irq(dev);
else
poll(dev);

type stuff.

NO_IRQ was intentionally removed from various platforms and really wants
kicking out of some others.

Alan
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