[PATCH 4.19 462/639] PM: ACPI/PCI: Resume all devices during hibernation

[Greg Kroah-Hartman]

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

[ Upstream commit 501debd4aa5edc755037c39ea5a8fba23b41e580 ]

Both the PCI bus type and the ACPI PM domain avoid resuming
runtime-suspended devices with DPM_FLAG_SMART_SUSPEND set during
hibernation (before creating the snapshot image of system memory),
but that turns out to be a mistake.  It leads to functional issues
and adds complexity that's hard to justify.

For this reason, resume all runtime-suspended PCI devices and all
devices in the ACPI PM domains before creating a snapshot image of
system memory during hibernation.

Fixes: 05087360fd7a (ACPI / PM: Take SMART_SUSPEND driver flag into account)
Fixes: c4b65157aeef (PCI / PM: Take SMART_SUSPEND driver flag into account)
Link: https://lore.kernel.org/linux-acpi/917d4399-2e22-67b1-9d54-808561f9083f@xxxxxxxx/T/#maf065fe6e4974f2a9d79f332ab99dfaba635f64c
Reported-by: Robert R. Howell <RHowell@xxxxxxxx>
Tested-by: Robert R. Howell <RHowell@xxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/acpi/device_pm.c | 13 +++++++------
 drivers/pci/pci-driver.c | 16 ++++++++--------
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index e0927c5fd2821..11b7a1632e5aa 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -1116,13 +1116,14 @@ EXPORT_SYMBOL_GPL(acpi_subsys_resume_early);
 int acpi_subsys_freeze(struct device *dev)
 {
 	/*
-	 * This used to be done in acpi_subsys_prepare() for all devices and
-	 * some drivers may depend on it, so do it here.  Ideally, however,
-	 * runtime-suspended devices should not be touched during freeze/thaw
-	 * transitions.
+	 * Resume all runtime-suspended devices before creating a snapshot
+	 * image of system memory, because the restore kernel generally cannot
+	 * be expected to always handle them consistently and they need to be
+	 * put into the runtime-active metastate during system resume anyway,
+	 * so it is better to ensure that the state saved in the image will be
+	 * always consistent with that.
 	 */
-	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND))
-		pm_runtime_resume(dev);
+	pm_runtime_resume(dev);
 
 	return pm_generic_freeze(dev);
 }
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index e69af9b8361dc..5def4b74d54a0 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -996,15 +996,15 @@ static int pci_pm_freeze(struct device *dev)
 	}
 
 	/*
-	 * This used to be done in pci_pm_prepare() for all devices and some
-	 * drivers may depend on it, so do it here.  Ideally, runtime-suspended
-	 * devices should not be touched during freeze/thaw transitions,
-	 * however.
+	 * Resume all runtime-suspended devices before creating a snapshot
+	 * image of system memory, because the restore kernel generally cannot
+	 * be expected to always handle them consistently and they need to be
+	 * put into the runtime-active metastate during system resume anyway,
+	 * so it is better to ensure that the state saved in the image will be
+	 * always consistent with that.
 	 */
-	if (!dev_pm_smart_suspend_and_suspended(dev)) {
-		pm_runtime_resume(dev);
-		pci_dev->state_saved = false;
-	}
+	pm_runtime_resume(dev);
+	pci_dev->state_saved = false;
 
 	if (pm->freeze) {
 		int error;
-- 
2.20.1