Commit 08a67024 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/pm' 

- Account for _S0W when deciding whether to put bridges in D3 to avoid
  missing hotplug events (Rafael J. Wysocki)

* pci/pm:
  PCI/ACPI: Account for _S0W of the target bridge in acpi_pci_bridge_d3()
parents 7260675a 8133844a

drivers/acpi/device_pm.c

+19 −0
Original line number Diff line number Diff line
@@ -484,6 +484,25 @@ void acpi_dev_power_up_children_with_adr(struct acpi_device *adev) 
	acpi_dev_for_each_child(adev, acpi_power_up_if_adr_present, NULL);

}



/**

 * acpi_dev_power_state_for_wake - Deepest power state for wakeup signaling

 * @adev: ACPI companion of the target device.

 *

 * Evaluate _S0W for @adev and return the value produced by it or return

 * ACPI_STATE_UNKNOWN on errors (including _S0W not present).

 */

u8 acpi_dev_power_state_for_wake(struct acpi_device *adev)

{

	unsigned long long state;

	acpi_status status;



	status = acpi_evaluate_integer(adev->handle, "_S0W", NULL, &state);

	if (ACPI_FAILURE(status))

		return ACPI_STATE_UNKNOWN;



	return state;

}



#ifdef CONFIG_PM

static DEFINE_MUTEX(acpi_pm_notifier_lock);

static DEFINE_MUTEX(acpi_pm_notifier_install_lock);

drivers/pci/pci-acpi.c

+31 −14
Original line number Diff line number Diff line
@@ -976,24 +976,41 @@ bool acpi_pci_power_manageable(struct pci_dev *dev) 
bool acpi_pci_bridge_d3(struct pci_dev *dev)

{

	struct pci_dev *rpdev;

	struct acpi_device *adev;

	acpi_status status;

	unsigned long long state;

	struct acpi_device *adev, *rpadev;

	const union acpi_object *obj;



	if (acpi_pci_disabled || !dev->is_hotplug_bridge)

		return false;



	/* Assume D3 support if the bridge is power-manageable by ACPI. */

	if (acpi_pci_power_manageable(dev))

	adev = ACPI_COMPANION(&dev->dev);

	if (adev) {

		/*

		 * If the bridge has _S0W, whether or not it can go into D3

		 * depends on what is returned by that object.  In particular,

		 * if the power state returned by _S0W is D2 or shallower,

		 * entering D3 should not be allowed.

		 */

		if (acpi_dev_power_state_for_wake(adev) <= ACPI_STATE_D2)

			return false;



		/*

		 * Otherwise, assume that the bridge can enter D3 so long as it

		 * is power-manageable via ACPI.

		 */

		if (acpi_device_power_manageable(adev))

			return true;

	}



	rpdev = pcie_find_root_port(dev);

	if (!rpdev)

		return false;



	adev = ACPI_COMPANION(&rpdev->dev);

	if (!adev)

	if (rpdev == dev)

		rpadev = adev;

	else

		rpadev = ACPI_COMPANION(&rpdev->dev);



	if (!rpadev)

		return false;



	/*
@@ -1001,15 +1018,15 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev) 
	 * doesn't supply a wakeup GPE via _PRW, it cannot signal hotplug

	 * events from low-power states including D3hot and D3cold.

	 */

	if (!adev->wakeup.flags.valid)

	if (!rpadev->wakeup.flags.valid)

		return false;



	/*

	 * If the Root Port cannot wake itself from D3hot or D3cold, we

	 * can't use D3.

	 * In the bridge-below-a-Root-Port case, evaluate _S0W for the Root Port

	 * to verify whether or not it can signal wakeup from D3.

	 */

	status = acpi_evaluate_integer(adev->handle, "_S0W", NULL, &state);

	if (ACPI_SUCCESS(status) && state < ACPI_STATE_D3_HOT)

	if (rpadev != adev &&

	    acpi_dev_power_state_for_wake(rpadev) <= ACPI_STATE_D2)

		return false;



	/*
@@ -1018,7 +1035,7 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev) 
	 * bridges *below* that Root Port can also signal hotplug events

	 * while in D3.

	 */

	if (!acpi_dev_get_property(adev, "HotPlugSupportInD3",

	if (!acpi_dev_get_property(rpadev, "HotPlugSupportInD3",

				   ACPI_TYPE_INTEGER, &obj) &&

	    obj->integer.value == 1)

		return true;

include/acpi/acpi_bus.h

+1 −0
Original line number Diff line number Diff line
@@ -533,6 +533,7 @@ int acpi_bus_update_power(acpi_handle handle, int *state_p); 
int acpi_device_update_power(struct acpi_device *device, int *state_p);

bool acpi_bus_power_manageable(acpi_handle handle);

void acpi_dev_power_up_children_with_adr(struct acpi_device *adev);

u8 acpi_dev_power_state_for_wake(struct acpi_device *adev);

int acpi_device_power_add_dependent(struct acpi_device *adev,

				    struct device *dev);

void acpi_device_power_remove_dependent(struct acpi_device *adev,