linux-kernel - [PATCH] PM / sleep / irq: Do not suspend wakeup interrupts

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Message-ID: <4679574.kGUnqAuNl9@vostro.rjw.lan>
Date:	Thu, 10 Jul 2014 23:37:54 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	"Li, Aubrey" <aubrey.li@...ux.intel.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	Linux PM list <linux-pm@...r.kernel.org>
Subject: [PATCH] PM / sleep / irq: Do not suspend wakeup interrupts

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

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@...el.com>
---
 kernel/irq/manage.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux-pm/kernel/irq/manage.c
===================================================================
--- linux-pm.orig/kernel/irq/manage.c
+++ linux-pm/kernel/irq/manage.c
@@ -385,7 +385,8 @@ setup_affinity(unsigned int irq, struct
 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;
 	}

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