Commit abf02e29 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pm-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm 

Pull power management fix from Rafael Wysocki:
 "Prevent PCI bridges in general (and PCIe ports in particular) from
  being put into low-power states during system-wide suspend transitions
  if there are any devices in D0 below them and refine the handling of
  PCI devices in D0 during suspend-to-idle cycles"

* tag 'pm-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PCI: PM: Skip devices in D0 for suspend-to-idle
parents c3c0d546 3e26c5fe

drivers/pci/pci-driver.c

+35 −12
Original line number Diff line number Diff line
@@ -524,7 +524,6 @@ static void pci_pm_default_resume_early(struct pci_dev *pci_dev) 
	pci_power_up(pci_dev);

	pci_restore_state(pci_dev);

	pci_pme_restore(pci_dev);

	pci_fixup_device(pci_fixup_resume_early, pci_dev);

}



/*
@@ -831,18 +830,16 @@ static int pci_pm_suspend_noirq(struct device *dev) 


	if (pci_dev->skip_bus_pm) {

		/*

		 * The function is running for the second time in a row without

		 * Either the device is a bridge with a child in D0 below it, or

		 * 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.

		 * suspend-to-idle in a spurious wakeup case.  The device should

		 * be in D0 at this point, but if it is a bridge, it may be

		 * necessary to save its state.

		 */

		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 {

		if (!pci_dev->state_saved)

			pci_save_state(pci_dev);

	} else if (!pci_dev->state_saved) {

		pci_save_state(pci_dev);

		if (pci_power_manageable(pci_dev))

			pci_prepare_to_sleep(pci_dev);
@@ -851,6 +848,22 @@ static int pci_pm_suspend_noirq(struct device *dev) 
	dev_dbg(dev, "PCI PM: Suspend power state: %s\n",

		pci_power_name(pci_dev->current_state));



	if (pci_dev->current_state == PCI_D0) {

		pci_dev->skip_bus_pm = true;

		/*

		 * Per PCI PM r1.2, table 6-1, a bridge must be in D0 if any

		 * downstream device is in D0, so avoid changing the power state

		 * of the parent bridge by setting the skip_bus_pm flag for it.

		 */

		if (pci_dev->bus->self)

			pci_dev->bus->self->skip_bus_pm = true;

	}



	if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) {

		dev_dbg(dev, "PCI PM: Skipped\n");

		goto Fixup;

	}



	pci_pm_set_unknown_state(pci_dev);



	/*
@@ -898,8 +911,17 @@ static int pci_pm_resume_noirq(struct device *dev) 
	if (dev_pm_smart_suspend_and_suspended(dev))

		pm_runtime_set_active(dev);



	/*

	 * In the suspend-to-idle case, devices left in D0 during suspend will

	 * stay in D0, so it is not necessary to restore or update their

	 * configuration here and attempting to put them into D0 again may

	 * confuse some firmware, so avoid doing that.

	 */

	if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware())

		pci_pm_default_resume_early(pci_dev);



	pci_fixup_device(pci_fixup_resume_early, pci_dev);



	if (pci_has_legacy_pm_support(pci_dev))

		return pci_legacy_resume_early(dev);
@@ -1194,6 +1216,7 @@ static int pci_pm_restore_noirq(struct device *dev) 
	}



	pci_pm_default_resume_early(pci_dev);

	pci_fixup_device(pci_fixup_resume_early, pci_dev);



	if (pci_has_legacy_pm_support(pci_dev))

		return pci_legacy_resume_early(dev);