Power management fixes for 5.2-rc3

- Modify the PCI bus type's PM code to avoid putting devices left
    by their drivers in D0 on purpose during suspend to idle into
    low-power states as doing that may confuse the system resume
    callbacks of the drivers in question (Rafael Wysocki).
 
  - Avoid checking ACPI wakeup configuration during system-wide
    suspend for suspended devices that do not use ACPI-based wakeup
    to allow them to stay in suspend more often (Rafael Wysocki).
 
  - The last phase of hibernation is analogous to system-wide suspend
    also because on platforms with ACPI it passes control to the
    platform firmware to complete the transision, so make it indicate
    that by calling pm_set_suspend_via_firmware() to allow the drivers
    that care about this to do the right thing (Rafael Wysocki).
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Merge tag 'pm-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix three issues in the system-wide suspend and hibernation area
  related to PCI device PM handling by suspend-to-idle, device wakeup
  optimizations and arbitrary differences between suspend and
  hiberantion.

  Specifics:

   - Modify the PCI bus type's PM code to avoid putting devices left by
     their drivers in D0 on purpose during suspend to idle into
     low-power states as doing that may confuse the system resume
     callbacks of the drivers in question (Rafael Wysocki).

   - Avoid checking ACPI wakeup configuration during system-wide suspend
     for suspended devices that do not use ACPI-based wakeup to allow
     them to stay in suspend more often (Rafael Wysocki).

   - The last phase of hibernation is analogous to system-wide suspend
     also because on platforms with ACPI it passes control to the
     platform firmware to complete the transision, so make it indicate
     that by calling pm_set_suspend_via_firmware() to allow the drivers
     that care about this to do the right thing (Rafael Wysocki)"

* tag 'pm-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PCI: PM: Avoid possible suspend-to-idle issue
  ACPI: PM: Call pm_set_suspend_via_firmware() during hibernation
  ACPI/PCI: PM: Add missing wakeup.flags.valid checks

drivers/acpi/device_pm.c

@@ -944,8 +944,8 @@ static bool acpi_dev_needs_resume(struct device *dev, struct acpi_device *adev)
 	u32 sys_target = acpi_target_system_state();
 	int ret, state;
 
-	if (!pm_runtime_suspended(dev) || !adev ||
-	    device_may_wakeup(dev) != !!adev->wakeup.prepare_count)
+	if (!pm_runtime_suspended(dev) || !adev || (adev->wakeup.flags.valid &&
+	    device_may_wakeup(dev) != !!adev->wakeup.prepare_count))
 		return true;
 
 	if (sys_target == ACPI_STATE_S0)

drivers/acpi/sleep.c

@@ -1132,17 +1132,21 @@ void __init acpi_no_s4_hw_signature(void)
 	nosigcheck = true;
 }
 
-static int acpi_hibernation_begin(void)
+static int acpi_hibernation_begin(pm_message_t stage)
 {
-	int error;
-
-	error = nvs_nosave ? 0 : suspend_nvs_alloc();
-	if (!error)
-		acpi_pm_start(ACPI_STATE_S4);
-
+	if (!nvs_nosave) {
+		int error = suspend_nvs_alloc();
+		if (error)
 			return error;
 	}
 
+	if (stage.event == PM_EVENT_HIBERNATE)
+		pm_set_suspend_via_firmware();
+
+	acpi_pm_start(ACPI_STATE_S4);
+	return 0;
+}
+
 static int acpi_hibernation_enter(void)
 {
 	acpi_status status = AE_OK;
@@ -1200,7 +1204,7 @@ static const struct platform_hibernation_ops acpi_hibernation_ops = {
  *		function is used if the pre-ACPI 2.0 suspend ordering has been
  *		requested.
  */
-static int acpi_hibernation_begin_old(void)
+static int acpi_hibernation_begin_old(pm_message_t stage)
 {
 	int error;
 	/*
@@ -1211,16 +1215,21 @@ static int acpi_hibernation_begin_old(void)
 	acpi_sleep_tts_switch(ACPI_STATE_S4);
 
 	error = acpi_sleep_prepare(ACPI_STATE_S4);
+	if (error)
+		return error;
 
-	if (!error) {
-		if (!nvs_nosave)
+	if (!nvs_nosave) {
 		error = suspend_nvs_alloc();
-		if (!error) {
+		if (error)
+			return error;
+	}
+
+	if (stage.event == PM_EVENT_HIBERNATE)
+		pm_set_suspend_via_firmware();
+
 	acpi_target_sleep_state = ACPI_STATE_S4;
 	acpi_scan_lock_acquire();
-		}
-	}
-	return error;
+	return 0;
 }
 
 /*

drivers/pci/pci-acpi.c

@@ -733,7 +733,8 @@ static bool acpi_pci_need_resume(struct pci_dev *dev)
 	if (!adev || !acpi_device_power_manageable(adev))
 		return false;
 
-	if (device_may_wakeup(&dev->dev) != !!adev->wakeup.prepare_count)
+	if (adev->wakeup.flags.valid &&
+	    device_may_wakeup(&dev->dev) != !!adev->wakeup.prepare_count)
 		return true;
 
 	if (acpi_target_system_state() == ACPI_STATE_S0)

drivers/pci/pci-driver.c

@@ -734,6 +734,8 @@ static int pci_pm_suspend(struct device *dev)
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
 
+	pci_dev->skip_bus_pm = false;
+
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_suspend(dev, PMSG_SUSPEND);
 
@@ -827,7 +829,20 @@ static int pci_pm_suspend_noirq(struct device *dev)
 		}
 	}
 
-	if (!pci_dev->state_saved) {
+	if (pci_dev->skip_bus_pm) {
+		/*
+		 * The function is running for the second time in a row without
+		 * going through full resume, which is possible only during
+		 * suspend-to-idle in a spurious wakeup case.  Moreover, the
+		 * device was originally left in D0, so its power state should
+		 * not be changed here and the device register values saved
+		 * originally should be restored on resume again.
+		 */
+		pci_dev->state_saved = true;
+	} else if (pci_dev->state_saved) {
+		if (pci_dev->current_state == PCI_D0)
+			pci_dev->skip_bus_pm = true;
+	} else {
 		pci_save_state(pci_dev);
 		if (pci_power_manageable(pci_dev))
 			pci_prepare_to_sleep(pci_dev);

include/linux/pci.h

@@ -344,6 +344,7 @@ struct pci_dev {
 						   D3cold, not set for devices
 						   powered on/off by the
 						   corresponding bridge */
+	unsigned int	skip_bus_pm:1;	/* Internal: Skip bus-level PM */
 	unsigned int	ignore_hotplug:1;	/* Ignore hotplug events */
 	unsigned int	hotplug_user_indicators:1; /* SlotCtl indicators
 						      controlled exclusively by

include/linux/suspend.h

@@ -359,7 +359,7 @@ extern void mark_free_pages(struct zone *zone);
  *	platforms which require special recovery actions in that situation.
  */
 struct platform_hibernation_ops {
-	int (*begin)(void);
+	int (*begin)(pm_message_t stage);
 	void (*end)(void);
 	int (*pre_snapshot)(void);
 	void (*finish)(void);

kernel/power/hibernate.c

@@ -129,7 +129,7 @@ static int hibernation_test(int level) { return 0; }
 static int platform_begin(int platform_mode)
 {
 	return (platform_mode && hibernation_ops) ?
-		hibernation_ops->begin() : 0;
+		hibernation_ops->begin(PMSG_FREEZE) : 0;
 }
 
 /**
@@ -542,7 +542,7 @@ int hibernation_platform_enter(void)
 	 * hibernation_ops->finish() before saving the image, so we should let
 	 * the firmware know that we're going to enter the sleep state after all
 	 */
-	error = hibernation_ops->begin();
+	error = hibernation_ops->begin(PMSG_HIBERNATE);
 	if (error)
 		goto Close;