Re: test for "spurious" IRQ ignores possible IRQ_WAKE_THREAD value

From: Thomas Gleixner
Date: Thu Sep 17 2009 - 15:52:47 EST


On Thu, 17 Sep 2009, Cyrill Gorcunov wrote:
> [Robert P. J. Day - Mon, Sep 14, 2009 at 04:34:48PM -0400]
> | On Mon, 14 Sep 2009, Robert P. J. Day wrote:
> |
> | > never ashamed to embarrass myself in public, i just noticed the
> | > following. from kernel/irq/spurious.c:
> | >
> | > ...
> | > static void
> | > __report_bad_irq(unsigned int irq, struct irq_desc *desc,
> | > irqreturn_t action_ret)
> | > {
> | > struct irqaction *action;
> | >
> | > if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
> | > printk(KERN_ERR "irq event %d: bogus return value %x\n",
> | > irq, action_ret);
> | >
> | > but from include/linux/irqreturn.h, we see *three* possible return
> | > values:
> | >
> | > enum irqreturn {
> | > IRQ_NONE,
> | > IRQ_HANDLED,
> | > IRQ_WAKE_THREAD,
> | > };
> | >
> | > typedef enum irqreturn irqreturn_t;
> | > #define IRQ_RETVAL(x) ((x) != IRQ_NONE)
> | >
> | > is there an inconsistency here?
> |
> ...
>
> Hi Robert,
>
> It could that IRQ_WAKE_THREAD is just missed here. I suppose it
> was brough there as thread irq merged. But I think only Thomas
> know for sure, I definitely miss something :) CC'ed

from kernel/irq/handle.c:

trace_irq_handler_entry(irq, action);
ret = action->handler(irq, action->dev_id);
trace_irq_handler_exit(irq, action, ret);

switch (ret) {
case IRQ_WAKE_THREAD:
/*
* Set result to handled so the spurious check
* does not trigger.
*/
ret = IRQ_HANDLED;

So nothing to worry about :)

Thanks,

tglx
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