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    SubjectRe: [patch, -rc5-mm1] locking validator: special rule: 8390.c disable_irq()
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    On Wed, 2006-05-31 at 23:47 +0200, Ingo Molnar wrote:
    > * Arjan van de Ven <arjan@infradead.org> wrote:
    >
    > > On Wed, 2006-05-31 at 17:41 -0400, Alan Cox wrote:
    > > > On Wed, May 31, 2006 at 10:31:40PM +0200, Arjan van de Ven wrote:
    > > > > > 8390.c knows that ei_local->page_lock can only be used by an irq
    > > > > > context that it disabled -
    > > > >
    > > > > btw I think this is no longer correct with the irq polling stuff Alan
    > > > > added to the kernel recently...
    > > >
    > > > We could make the misrouted IRQ logic skip all handlers on a disabled IRQ
    > > > but that might actually be worse than the disease we are trying to cure by
    > > > doing so.
    > >
    > > yeah since misrouted irqs will cause the kernel do disable irqs 'at
    > > random' more or less .. for which the handlers now would become
    > > unreachable which isn't good.
    >
    > couldnt most of these problems be avoided by tracking whether a handler
    > _ever_ returned a success status? That means that irqpoll could safely
    > poll handlers for which we know that they somehow arent yet matched up
    > to any IRQ line?

    I suspect the real solution is to have a

    disable_irq_handler(irq, handler)

    function which does 2 things
    1) disable the irq at the hardware level
    2) mark the handler as "don't call me"

    it matches the semantics here; what these drivers want is 1) not get an
    irq handler called and 2) not get an irq flood


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