From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux ACPI <linux-acpi@vger.kernel.org>
Cc: Linux PM <linux-pm@vger.kernel.org>,
Linux PCI <linux-pci@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Bjorn Helgaas <helgaas@kernel.org>,
Mario Limonciello <mario.limonciello@dell.com>,
Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: [PATCH] ACPI: PM: Fix regression in acpi_device_set_power()
Date: Thu, 01 Aug 2019 01:31:08 +0200 [thread overview]
Message-ID: <4199592.UtrPOv3ZmA@kreacher> (raw)
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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>
---
drivers/acpi/device_pm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/acpi/device_pm.c
===================================================================
--- linux-pm.orig/drivers/acpi/device_pm.c
+++ linux-pm/drivers/acpi/device_pm.c
@@ -236,13 +236,15 @@ int acpi_device_set_power(struct acpi_de
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. */
next reply other threads:[~2019-07-31 23:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 23:31 Rafael J. Wysocki [this message]
2019-08-01 6:11 ` [PATCH] ACPI: PM: Fix regression in acpi_device_set_power() Kai-Heng Feng
2019-08-01 19:06 ` Mario.Limonciello
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