Power management fixes for 4.18-rc4

- Resume parallel PCI (non-PCIe) bridges on suspend-to-RAM (ACP S3)
    to avoid confusing the platform firmware which started to happen
    after a core power management regression fix that went in during
    the 4.17 cycle (Rafael Wysocki).
 
  - Fix up the recently added support for devices in multiple power
    domains by avoiding to power up the entire domain unnecessarily
    when attaching a device to it (Ulf Hansson).
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Merge tag 'pm-4.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix a PCI power management regression introduced during the 4.17
  cycle and fix up the recently added support for devices in multiple
  power domains.

  Specifics:

   - Resume parallel PCI (non-PCIe) bridges on suspend-to-RAM (ACP S3)
     to avoid confusing the platform firmware which started to happen
     after a core power management regression fix that went in during
     the 4.17 cycle (Rafael Wysocki).

   - Fix up the recently added support for devices in multiple power
     domains by avoiding to power up the entire domain unnecessarily
     when attaching a device to it (Ulf Hansson)"

* tag 'pm-4.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / Domains: Don't power on at attach for the multi PM domain case
  PCI / ACPI / PM: Resume bridges w/o drivers on suspend-to-RAM

drivers/base/power/domain.c

@@ -2235,7 +2235,7 @@ static void genpd_dev_pm_sync(struct device *dev)
 }
 
 static int __genpd_dev_pm_attach(struct device *dev, struct device_node *np,
-				 unsigned int index)
+				 unsigned int index, bool power_on)
 {
 	struct of_phandle_args pd_args;
 	struct generic_pm_domain *pd;
@@ -2271,9 +2271,11 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device_node *np,
 	dev->pm_domain->detach = genpd_dev_pm_detach;
 	dev->pm_domain->sync = genpd_dev_pm_sync;
 
-	genpd_lock(pd);
-	ret = genpd_power_on(pd, 0);
-	genpd_unlock(pd);
+	if (power_on) {
+		genpd_lock(pd);
+		ret = genpd_power_on(pd, 0);
+		genpd_unlock(pd);
+	}
 
 	if (ret)
 		genpd_remove_device(pd, dev);
@@ -2307,7 +2309,7 @@ int genpd_dev_pm_attach(struct device *dev)
 				       "#power-domain-cells") != 1)
 		return 0;
 
-	return __genpd_dev_pm_attach(dev, dev->of_node, 0);
+	return __genpd_dev_pm_attach(dev, dev->of_node, 0, true);
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
 
@@ -2359,14 +2361,14 @@ struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 	}
 
 	/* Try to attach the device to the PM domain at the specified index. */
-	ret = __genpd_dev_pm_attach(genpd_dev, dev->of_node, index);
+	ret = __genpd_dev_pm_attach(genpd_dev, dev->of_node, index, false);
 	if (ret < 1) {
 		device_unregister(genpd_dev);
 		return ret ? ERR_PTR(ret) : NULL;
 	}
 
-	pm_runtime_set_active(genpd_dev);
 	pm_runtime_enable(genpd_dev);
+	genpd_queue_power_off_work(dev_to_genpd(genpd_dev));
 
 	return genpd_dev;
 }

drivers/pci/pci-acpi.c

@@ -629,6 +629,18 @@ static bool acpi_pci_need_resume(struct pci_dev *dev)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
 
+	/*
+	 * In some cases (eg. Samsung 305V4A) leaving a bridge in suspend over
+	 * system-wide suspend/resume confuses the platform firmware, so avoid
+	 * doing that, unless the bridge has a driver that should take care of
+	 * the PM handling.  According to Section 16.1.6 of ACPI 6.2, endpoint
+	 * devices are expected to be in D3 before invoking the S3 entry path
+	 * from the firmware, so they should not be affected by this issue.
+	 */
+	if (pci_is_bridge(dev) && !dev->driver &&
+	    acpi_target_system_state() != ACPI_STATE_S0)
+		return true;
+
 	if (!adev || !acpi_device_power_manageable(adev))
 		return false;