PM / sleep / irq: Do not suspend wakeup interrupts

This change “PM / sleep / irq: Do not suspend wakeup interrupts” (commit d709f7b) in Linux kernel is authored by Rafael J. Wysocki <rafael.j.wysocki [at] intel.com> on Thu Jul 10 23:37:54 2014 +0200.

Description of "PM / sleep / irq: Do not suspend wakeup interrupts"

The change “PM / sleep / irq: Do not suspend wakeup interrupts” introduces changes as follows.

PM / sleep / irq: Do not suspend wakeup interrupts

If an IRQ has been configured for wakeup via enable_irq_wake(), the
driver who has done that must be prepared for receiving interrupts
after suspend_device_irqs() has returned, so there is no need to
"suspend" such IRQs.  Moreover, if drivers using enable_irq_wake()
actually want to receive interrupts after suspend_device_irqs() has
returned, they need to add IRQF_NO_SUSPEND to the IRQ flags while
requesting the IRQs, which shouldn't be necessary (it also goes a bit
too far, as IRQF_NO_SUSPEND causes the IRQ to be ignored by
suspend_device_irqs() all the time regardless of whether or not it
has been configured for signaling wakeup).

For the above reasons, make __disable_irq() ignore IRQ descriptors
with IRQD_WAKEUP_STATE set when its suspend argument is true which
effectively causes them to behave like IRQs with IRQF_NO_SUSPEND
set.

This also allows IRQs configured for wakeup via enable_irq_wake()
to work as wakeup interrupts for the "freeze" (suspend-to-idle)
sleep mode automatically just like for any other sleep states.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Li Aubrey <aubrey.li@linux.intel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Link: http://lkml.kernel.org/r/4679574.kGUnqAuNl9@vostro.rjw.lan
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Linux kernel releases containing commit d709f7b

The Linux kernel releases containing this commit are as follows.

Linux kernel code changes from "PM / sleep / irq: Do not suspend wakeup interrupts"

There are 3 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 kernel/irq/manage.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
 
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3dc6a61bf06a..88657d7bc9dd 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -385,7 +385,8 @@ setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 {
 	if (suspend) {
-		if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
+		if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND) ||
+		    irqd_has_set(&desc->irq_data, IRQD_WAKEUP_STATE))
 			return;
 		desc->istate |= IRQS_SUSPENDED;
 	}

The commit for this change in Linux stable tree is d709f7b (patch).

Last modified: 2020/02/10