linux-kernel - Re: test for "spurious" IRQ ignores possible IRQ_WAKE

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Date:	Mon, 14 Sep 2009 16:34:48 -0400 (EDT)
From:	"Robert P. J. Day" <rpjday@...shcourse.ca>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: test for "spurious" IRQ ignores possible IRQ_WAKE_THREAD value

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?

  i should have pointed out that there is (apparently) only one place
in the entire tree that uses that third return value:

$ grep -rw IRQ_WAKE_THREAD *
drivers/net/wireless/b43/main.c:	return IRQ_WAKE_THREAD;  <-- there
include/linux/irqreturn.h: * @IRQ_WAKE_THREAD	handler requests to wake the handler thread
include/linux/irqreturn.h:	IRQ_WAKE_THREAD,
Binary file include/linux/.irqreturn.h.swp matches
include/linux/interrupt.h: * IRQTF_WARNED    - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed
kernel/irq/handle.c:	printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
kernel/irq/handle.c:		case IRQ_WAKE_THREAD:
kernel/irq/manage.c:	return IRQ_WAKE_THREAD;
kernel/irq/manage.c: *	IRQ_WAKE_THREAD which will wake up the handler thread and run
$

  for what that's worth.

rday
--

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

        Linux Consulting, Training and Annoying Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
========================================================================
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