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

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 818b2802d3e79f8a8d358f212b957f7298fe5318..3089a60ea8f98ffeb58c0d497d1172cc15718e1e 100644 (file)
--- 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)
 {