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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: bebarino

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)
 {