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    SubjectRe: [PATCH] serial: Use real irq on UART0 (IRQ = 0) on PPC4xx systems
    On Monday 20 November 2006 12:42, Alan wrote:
    > On Mon, 20 Nov 2006 12:00:36 +0100
    >
    > Stefan Roese <ml@stefan-roese.de> wrote:
    > > This patch fixes a problem seen on multiple 4xx platforms, where
    > > the UART0 interrupt number is 0. The macro "is_real_interrupt" lead
    > > on those systems to not use an real interrupt but the timer based
    > > implementation.
    >
    > NAK.

    I knew it. ;-)

    > Zero means "no interrupt" in the Linux space. If you have a physical IRQ
    > 0 remap it to a convenient number (eg map IRQ's + 1, or stick it on the
    > end). The logical and physical IRQ numbering in Linux don't have to match
    > up - and given some platforms have IRQ numbering per bus and the like
    > clearly doesn't in many cases.

    Let's see, if I got this right. You mean that on such a platform, where 0 is a
    valid physical IRQ, we should assign another value as virtual IRQ number (not
    0 and not -1 of course). And then the platform "pic" implementation should
    take care of the remapping of these virtual IRQ numbers to the physical
    numbers.

    Correct?

    Best regards,
    Stefan
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