ACPI: PM: s2idle: Check fixed wakeup events in acpi_s2idle_wake()

Commit fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from
waking up the system") overlooked the fact that fixed events can wake
up the system too and broke RTC wakeup from suspend-to-idle as a
result.

Fix this issue by checking the fixed events in acpi_s2idle_wake() in
addition to checking wakeup GPEs and break out of the suspend-to-idle
loop if the status bits of any enabled fixed events are set then.

Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Reported-and-tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 52 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/evevent.c b/drivers/acpi/acpica/evevent.c
index 8c83d8c620dc..789d5e920aaf 100644
--- a/drivers/acpi/acpica/evevent.c
+++ b/drivers/acpi/acpica/evevent.c
@@ -265,4 +265,49 @@ static u32 acpi_ev_fixed_event_dispatch(u32 event)
 		 handler) (acpi_gbl_fixed_event_handlers[event].context));
 }
 
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_any_fixed_event_status_set
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      TRUE or FALSE
+ *
+ * DESCRIPTION: Checks the PM status register for active fixed events
+ *
+ ******************************************************************************/
+
+u32 acpi_any_fixed_event_status_set(void)
+{
+	acpi_status status;
+	u32 in_status;
+	u32 in_enable;
+	u32 i;
+
+	status = acpi_hw_register_read(ACPI_REGISTER_PM1_ENABLE, &in_enable);
+	if (ACPI_FAILURE(status)) {
+		return (FALSE);
+	}
+
+	status = acpi_hw_register_read(ACPI_REGISTER_PM1_STATUS, &in_status);
+	if (ACPI_FAILURE(status)) {
+		return (FALSE);
+	}
+
+	/*
+	 * Check for all possible Fixed Events and dispatch those that are active
+	 */
+	for (i = 0; i < ACPI_NUM_FIXED_EVENTS; i++) {
+
+		/* Both the status and enable bits must be on for this event */
+
+		if ((in_status & acpi_gbl_fixed_event_info[i].status_bit_mask) &&
+		    (in_enable & acpi_gbl_fixed_event_info[i].enable_bit_mask)) {
+			return (TRUE);
+		}
+	}
+
+	return (FALSE);
+}
+
 #endif				/* !ACPI_REDUCED_HARDWARE */
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 152f7fc0b200..e5f95922bc21 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -1006,6 +1006,13 @@ static bool acpi_s2idle_wake(void)
 			return true;
 
 		/*
+		 * If the status bit of any enabled fixed event is set, the
+		 * wakeup is regarded as valid.
+		 */
+		if (acpi_any_fixed_event_status_set())
+			return true;
+
+		/*
 		 * 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.