linux-kernel - [tip: irq/urgent] genirq: Clarify that irq wake state is orthogonal to enable/disable

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Date:   Fri, 07 Feb 2020 20:40:53 -0000
From:   "tip-bot2 for Stephen Boyd" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Stephen Boyd <swboyd@...omium.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Douglas Anderson <dianders@...omium.org>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: irq/urgent] genirq: Clarify that irq wake state is orthogonal
 to enable/disable

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     f9f21cea311340f38074ff93a8d89b4a9cae6bcc
Gitweb:        https://git.kernel.org/tip/f9f21cea311340f38074ff93a8d89b4a9cae6bcc
Author:        Stephen Boyd <swboyd@...omium.org>
AuthorDate:    Thu, 06 Feb 2020 11:15:21 -08:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 07 Feb 2020 21:37:08 +01:00

genirq: Clarify that irq wake state is orthogonal to enable/disable

There's some confusion around if an irq that's disabled with disable_irq()
can still wake the system from sleep states such as "suspend to RAM".

Clarify this in the kernel documentation for irq_set_irq_wake() so that
it's clear that an irq can be disabled and still wake the system if it has
been marked for wakeup.

Signed-off-by: Stephen Boyd <swboyd@...omium.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Douglas Anderson <dianders@...omium.org>
Link: https://lkml.kernel.org/r/20200206191521.94559-1-swboyd@chromium.org

---
 kernel/irq/manage.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 818b280..3089a60 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -731,6 +731,13 @@ static int set_irq_wake_real(unsigned int irq, unsigned int on)
  *
  *	Wakeup mode lets this IRQ wake the system from sleep
  *	states like "suspend to RAM".
+ *
+ *	Note: irq enable/disable state is completely orthogonal
+ *	to the enable/disable state of irq wake. An irq can be
+ *	disabled with disable_irq() and still wake the system as
+ *	long as the irq has wake enabled. If this does not hold,
+ *	then the underlying irq chip and the related driver need
+ *	to be investigated.
  */
 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 {