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    SubjectRe: [PATCH 2/2] uio: add an of_genirq driver
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    On Mon, 2009-06-15 at 00:12 +0100, Alan Cox wrote:
    > > > + if (!uioinfo->irq)
    > > > + uioinfo->irq = UIO_IRQ_NONE;
    > >
    > > Please don't do this. It's inconsistent if all other UIO drivers require
    > > people to use UIO_IRQ_NONE and you also allow zero. UIO_IRQ_NONE was
    > > introduced because 0 may be a legal interrupt number on some platforms.
    >
    > Zero is not a valid IRQ number in the kernel (except in arch specific
    > depths). IRQ numbers are also *unsigned* so -1 isn't a safe definition.
    >
    > Zero means no IRQ. If any old UIO code is assuming otherwise it wants
    > fixing.
    >
    > It is the job of the platform to map a physical IRQ 0 to some other
    > representation if it exists outside of arch specific code. This was
    > decided some years ago and a large part of the kernel simply doesn't
    > support any notion of a real IRQ 0.

    Right, and powerpc complies with that rule, so 0 is fine for us.

    Cheers,
    Ben.



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