linux-kernel - [PATCH v2] genirq: Clarify that irq wake state is orthogonal to enable/disable

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Message-Id: <20200206191521.94559-1-swboyd@chromium.org>
Date:   Thu,  6 Feb 2020 11:15:21 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, Marc Zyngier <maz@...nel.org>,
        Douglas Anderson <dianders@...omium.org>,
        Lina Iyer <ilina@...eaurora.org>,
        Maulik Shah <mkshah@...eaurora.org>
Subject: [PATCH v2] 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". Let's 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.

Cc: Marc Zyngier <maz@...nel.org>
Cc: Douglas Anderson <dianders@...omium.org>
Cc: Lina Iyer <ilina@...eaurora.org>
Cc: Maulik Shah <mkshah@...eaurora.org>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---

Changes from v1:
 * Added the last sentence from tglx

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

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 818b2802d3e7..e1e217d7778c 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 either the underlying irq chip and the related driver
+ *	need to be investigated.
  */
 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 {
-- 
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