On Wednesday, March 04, 2015 08:00:40 PM Mark Rutland wrote: > With certain restrictions it is possible for a wakeup device to share > and IRQ with an IRQF_NO_SUSPEND user, and the warnings introduced by > commit cab303be91dc47942bc25de33dc1140123540800 are spurious. The new > IRQF_COND_SUSPEND flag allows drivers to tell the core when these > restrictions are met, allowing spurious warnings to be silenced. > > This patch documents how IRQF_COND_SUSPEND is expected to be used, > updating some of the text now made invalid by its addition. > > Signed-off-by: Mark Rutland <[email protected]> > Cc: Boris Brezillon <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Rafael J. Wysocki <[email protected]> > --- > Documentation/power/suspend-and-interrupts.txt | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > As promised previously, take IRQF_COND_SUSPEND into account in the > documentation. > > Rafael, does this look OK to you?
Yes, it does, thanks! I'll queue it up along with the rest of the IRQF_COND_SUSPEND patches. > diff --git a/Documentation/power/suspend-and-interrupts.txt > b/Documentation/power/suspend-and-interrupts.txt > index 50493c9..8afb29a 100644 > --- a/Documentation/power/suspend-and-interrupts.txt > +++ b/Documentation/power/suspend-and-interrupts.txt > @@ -112,8 +112,9 @@ any special interrupt handling logic for it to work. > IRQF_NO_SUSPEND and enable_irq_wake() > ------------------------------------- > > -There are no valid reasons to use both enable_irq_wake() and the > IRQF_NO_SUSPEND > -flag on the same IRQ. > +There are very few valid reasons to use both enable_irq_wake() and the > +IRQF_NO_SUSPEND flag on the same IRQ, and it is never valid to use both for > the > +same device. > > First of all, if the IRQ is not shared, the rules for handling > IRQF_NO_SUSPEND > interrupts (interrupt handlers are invoked after suspend_device_irqs()) are > @@ -122,4 +123,13 @@ handlers are not invoked after suspend_device_irqs()). > > Second, both enable_irq_wake() and IRQF_NO_SUSPEND apply to entire IRQs and > not > to individual interrupt handlers, so sharing an IRQ between a system wakeup > -interrupt source and an IRQF_NO_SUSPEND interrupt source does not make sense. > +interrupt source and an IRQF_NO_SUSPEND interrupt source does not generally > +make sense. > + > +In rare cases an IRQ can be shared between a wakeup device driver and an > +IRQF_NO_SUSPEND user. In order for this to be safe, the wakeup device driver > +must be able to discern spurious IRQs from genuine wakeup events (signalling > +the latter to the core with pm_system_wakeup()), must use enable_irq_wake() > to > +ensure that the IRQ will function as a wakeup source, and must request the > IRQ > +with IRQF_COND_SUSPEND to tell the core that it meets these requirements. If > +these requirements are not met, it is not valid to use IRQF_COND_SUSPEND. > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
