[PATCH 2/2] ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

If the platform triggers a spurious SCI even though the status bit
is not set for any GPE when the system is suspended to idle, it will
be treated as a genuine wakeup, so avoid that by checking if any GPEs
are active at all before returning 'true' from acpi_s2idle_wake().

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206413
Fixes: 56b991849009 ("PM: sleep: Simplify suspend-to-idle control flow")
Reported-by: Tsuchiya Yuto <kitakar@xxxxxxxxx>
Cc: 5.4+ <stable@xxxxxxxxxxxxxxx> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/acpi/sleep.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/acpi/sleep.c
===================================================================
--- linux-pm.orig/drivers/acpi/sleep.c
+++ linux-pm/drivers/acpi/sleep.c
@@ -1006,10 +1006,16 @@ static bool acpi_s2idle_wake(void)
 			return true;
 
 		/*
-		 * If there are no EC events to process, the wakeup is regarded
-		 * as a genuine one.
+		 * If there are no EC events to process and at least one of the
+		 * other enabled GPEs is active, the wakeup is regarded as a
+		 * genuine one.
+		 *
+		 * Note that the checks below must be carried out in this order
+		 * to avoid returning prematurely due to a change of the EC GPE
+		 * status bit from unset to set between the checks with the
+		 * status bits of all the other GPEs unset.
 		 */
-		if (!acpi_ec_dispatch_gpe())
+		if (acpi_any_gpe_status_set() && !acpi_ec_dispatch_gpe())
 			return true;
 
 		/*