genirq: Allow check_wakeup_irqs to notice level-triggered interrupts

Level triggered interrupts do not cause IRQS_PENDING to be set when
they fire while "disabled" as the 'pending' state is always present in
the level - they automatically refire where re-enabled.

However the IRQS_PENDING flag is also used to abort a suspend cycle -
if any 'is_wakeup_set' interrupt is PENDING, check_wakeup_irqs() will
cause suspend to abort. Without IRQS_PENDING, suspend won't abort.

Consequently, level-triggered interrupts that fire during the 'noirq'
phase of suspend do not currently abort suspend.

So set IRQS_PENDING even for level triggered interrupts, and make sure
to clear the flag in check_irq_resend.

[ Changelog by courtesy of Neil ]

Tested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 2 deletions

diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index 14dd5761e8c9..6454db7b6a4d 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -58,10 +58,13 @@ void check_irq_resend(struct irq_desc *desc, unsigned int irq)
         /*
          * We do not resend level type interrupts. Level type
          * interrupts are resent by hardware when they are still
-         * active.
+         * active. Clear the pending bit so suspend/resume does not
+         * get confused.
          */
-        if (irq_settings_is_level(desc))
+        if (irq_settings_is_level(desc)) {
+                desc->istate &= ~IRQS_PENDING;
                 return;
+        }
         if (desc->istate & IRQS_REPLAY)
                 return;
         if (desc->istate & IRQS_PENDING) {