RE: [PATCH] ACPICA: Clear status of all events when entering sleep states

-----Original Message-----
From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
owner@vger.kernel.org] On Behalf Of Rafael J. Wysocki
Sent: Sunday, August 12, 2018 3:50 AM
To: Linux ACPI <redacted>
Cc: Paul Menzel <redacted>; Linux PM <linux-
pm@vger.kernel.org>; LKML [off-list ref]; Schmauss, Erik
[off-list ref]
Subject: [PATCH] ACPICA: Clear status of all events when entering sleep states

From: Rafael J. Wysocki <redacted>

Commit fa85015c0d95 (ACPICA: Clear status of all events when entering
S5) made the sleep state entry code in ACPICA clear the status of all ACPI events
when entering S5 to fix a functional regression reported against commit
18996f2db918 (ACPICA: Events: Stop unconditionally clearing ACPI IRQs during
suspend/resume).  However, it is reported now that the regression also affects
system states other than S5 on some systems and causes them to wake up from
sleep prematurely.

For this reason, make the code in question clear the status of all ACPI events
when entering all sleep states (in addition to S5) to avoid the premature
wakeups (this may cause some wakeup events to be missed in theory, but the
likelihood of that is small and the change here simply restores the previous
behavior of the code).

Fixes: 18996f2db918 (ACPICA: Events: Stop unconditionally clearing ACPI IRQs
during suspend/resume)
Reported-by: Paul Menzel <redacted>
Tested-by: Paul Menzel <redacted>
Cc: 4.17+ <redacted> # 4.17+: fa85015c0d95 ACPICA: Clear
status ...
Signed-off-by: Rafael J. Wysocki <redacted>
---
 drivers/acpi/acpica/hwsleep.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

Index: linux-pm/drivers/acpi/acpica/hwsleep.c
=================================================================
==

--- linux-pm.orig/drivers/acpi/acpica/hwsleep.c
+++ linux-pm/drivers/acpi/acpica/hwsleep.c

@@ -56,14 +56,9 @@ acpi_status acpi_hw_legacy_sleep(u8 slee
 	if (ACPI_FAILURE(status)) {
 		return_ACPI_STATUS(status);
 	}
-	/*
-	 * If the target sleep state is S5, clear all GPEs and fixed events too
-	 */
-	if (sleep_state == ACPI_STATE_S5) {
-		status = acpi_hw_clear_acpi_status();
-		if (ACPI_FAILURE(status)) {
-			return_ACPI_STATUS(status);
-		}
+	status = acpi_hw_clear_acpi_status();
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
 	}
 	acpi_gbl_system_awake_and_running = FALSE;