This allows entering and exiting s2idle. Actual S0ix residency is
another topic [1].

Without this the ACPI code currently ignores the error enable_irq_wake()
returns when being used on a xen-pirq and the system goes to idle for
ever since the wakeup IRQ doesn't gets enabled. With [2] the error is
handled and the system refuses to go to s2idle.

Link: https://lore.kernel.org/xen-devel/9051e484-b128-715a-9253-48af8e47bb9d@invisiblethingslab.com/ # [1]
Link: https://lore.kernel.org/linux-acpi/20230313125344.2893-1-simon@invisiblethingslab.com/ # [2]
Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com>
---

While I think that the set of flags I set is correct, I'm not familiar
with that code, so please pay special attention during review if they
are actually correct for xen-pirq.

 drivers/xen/events/events_base.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index c7715f8bd452..991082f04f05 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -2176,6 +2176,10 @@ static struct irq_chip xen_pirq_chip __read_mostly = {
 	.irq_set_affinity	= set_affinity_irq,
 
 	.irq_retrigger		= retrigger_dynirq,
+
+	.flags                  = IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND |
+				  IRQCHIP_MASK_ON_SUSPEND,
 };
 
 static struct irq_chip xen_percpu_chip __read_mostly = {
-- 
2.39.2