PM: ACPI/PCI: Resume all devices during hibernation

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@uwyo.edu/T/#maf065fe6e4974f2a9d79f332ab99dfaba635f64c
Reported-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>

2 files changed, 15 insertions, 14 deletions

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index e54956ae93d3..44172eb18d6e 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -1112,13 +1112,14 @@ 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 5eadbc3d0969..ce54fa3ed94a 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -972,15 +972,15 @@ 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;