Input: i8042 - enable keyboard wakeups by default when s2idle is used

Previously, on typical consumer laptops, pressing a key on the keyboard
when the system is in suspend would cause it to wake up (default or
unconditional behaviour). This happens because the EC generates a SCI
interrupt in this scenario.

That is no longer true on modern laptops based on Intel WhiskeyLake,
including Acer Swift SF314-55G, Asus UX333FA, Asus UX433FN and Asus
UX533FD. We confirmed with Asus EC engineers that the "Modern Standby"
design has been modified so that the EC no longer generates a SCI
in this case; the keyboard controller itself should be used for wakeup.

In order to retain the standard behaviour of being able to use the
keyboard to wake up the system, enable serio wakeups by default on
platforms that are using s2idle.

Link: https://lkml.kernel.org/r/CAB4CAwfQ0mPMqCLp95TVjw4J0r5zKPWkSvvkK4cpZUGE--w8bQ@mail.gmail.com
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

kernel/power/suspend.c

@@ -62,6 +62,12 @@ static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head);
 enum s2idle_states __read_mostly s2idle_state;
 static DEFINE_SPINLOCK(s2idle_lock);
 
+bool pm_suspend_via_s2idle(void)
+{
+	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
+}
+EXPORT_SYMBOL_GPL(pm_suspend_via_s2idle);
+
 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
 {
 	lock_system_sleep();