From 42787ed79638dc7f0f8d5c164caba1e87bfab50f Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Thu, 1 Aug 2019 01:31:08 +0200
Subject: [PATCH] ACPI: PM: Fix regression in acpi_device_set_power()
Git-commit: 42787ed79638dc7f0f8d5c164caba1e87bfab50f
Patch-mainline: 5.3-rc3
References: bsc#1051510
Commit f850a48a0799 ("ACPI: PM: Allow transitions to D0 to occur in
special cases") overlooked the fact that acpi_power_transition() may
change the power.state value for the target device and if that
happens, it may confuse acpi_device_set_power() and cause it to
omit the _PS0 evaluation which on some systems is necessary to
change power states of devices from low-power to D0.
Fix that by saving the current value of power.state for the
target device before passing it to acpi_power_transition() and
using the saved value in a subsequent check.
Fixes: f850a48a0799 ("ACPI: PM: Allow transitions to D0 to occur in special cases")
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reported-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Mario Limonciello <mario.limonciello@dell.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/acpi/device_pm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 28cffaaf9d82..f616b16c1f0b 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -232,13 +232,15 @@ int acpi_device_set_power(struct acpi_device *device, int state)
if (device->power.flags.power_resources)
result = acpi_power_transition(device, target_state);
} else {
+ int cur_state = device->power.state;
+
if (device->power.flags.power_resources) {
result = acpi_power_transition(device, ACPI_STATE_D0);
if (result)
goto end;
}
- if (device->power.state == ACPI_STATE_D0) {
+ if (cur_state == ACPI_STATE_D0) {
int psc;
/* Nothing to do here if _PSC is not present. */
--
2.16.4