PM: ACPI/PCI: Resume all devices during hibernation

[ Upstream commit 501debd4 ]

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: 05087360 (ACPI / PM: Take SMART_SUSPEND driver flag into account)
Fixes: c4b65157 (PCI / PM: Take SMART_SUSPEND driver flag into account)
Link: https://lore.kernel.org/linux-acpi/917d4399-2e22-67b1-9d54-808561f9083f@uwyo.edu/T/#maf065fe6e4974f2a9d79f332ab99dfaba635f64cReported-by: Robert R. Howell <RHowell@uwyo.edu>
Tested-by: Robert R. Howell <RHowell@uwyo.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/acpi/device_pm.c

@@ -1116,12 +1116,13 @@ 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);
 
 	return pm_generic_freeze(dev);

drivers/pci/pci-driver.c

@@ -959,15 +959,15 @@ 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;
-	}
 
 	if (pm->freeze) {
 		int error;