Commit 25eed407 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Len Brown
Browse files

ACPI / PM: Add function for updating device power state consistently 



Add function acpi_bus_update_power() for reading the actual power
state of an ACPI device and updating its device->power.state field
in such a way that its power resources' reference counters will
remain consistent with that field.

For this purpose introduce __acpi_bus_set_power() setting the
power state of an ACPI device without updating its
device->power.state field and make acpi_bus_set_power() and
acpi_bus_update_power() use it (acpi_bus_set_power() retains the
current behavior for now).

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent ade3e7fe

drivers/acpi/bus.c

+61 −29
Original line number Diff line number Diff line
@@ -255,44 +255,17 @@ int acpi_bus_get_power(acpi_handle handle, int *state) 
EXPORT_SYMBOL(acpi_bus_get_power);





int acpi_bus_set_power(acpi_handle handle, int state)

static int __acpi_bus_set_power(struct acpi_device *device, int state)

{

	int result = 0;

	acpi_status status = AE_OK;

	struct acpi_device *device = NULL;

	char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };





	result = acpi_bus_get_device(handle, &device);

	if (result)

		return result;



	if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))

	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))

		return -EINVAL;



	/* Make sure this is a valid target state */



	if (!device->flags.power_manageable) {

		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",

				kobject_name(&device->dev.kobj)));

		return -ENODEV;

	}

	/*

	 * Get device's current power state

	 */

	if (!acpi_power_nocheck) {

		/*

		 * Maybe the incorrect power state is returned on the bogus

		 * bios, which is different with the real power state.

		 * For example: the bios returns D0 state and the real power

		 * state is D3. OS expects to set the device to D0 state. In

		 * such case if OS uses the power state returned by the BIOS,

		 * the device can't be transisted to the correct power state.

		 * So if the acpi_power_nocheck is set, it is unnecessary to

		 * get the power state by calling acpi_bus_get_power.

		 */

		acpi_bus_get_power(device->handle, &device->power.state);

	}

	if ((state == device->power.state) && !device->flags.force_power_state) {

		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",

				  state));
@@ -362,6 +335,42 @@ int acpi_bus_set_power(acpi_handle handle, int state) 
	return result;

}





int acpi_bus_set_power(acpi_handle handle, int state)

{

	struct acpi_device *device;

	int result;



	result = acpi_bus_get_device(handle, &device);

	if (result)

		return result;



	if (!device->flags.power_manageable) {

		ACPI_DEBUG_PRINT((ACPI_DB_INFO,

				"Device [%s] is not power manageable\n",

				dev_name(&device->dev)));

		return -ENODEV;

	}



	/*

	 * Get device's current power state

	 */

	if (!acpi_power_nocheck) {

		/*

		 * Maybe the incorrect power state is returned on the bogus

		 * bios, which is different with the real power state.

		 * For example: the bios returns D0 state and the real power

		 * state is D3. OS expects to set the device to D0 state. In

		 * such case if OS uses the power state returned by the BIOS,

		 * the device can't be transisted to the correct power state.

		 * So if the acpi_power_nocheck is set, it is unnecessary to

		 * get the power state by calling acpi_bus_get_power.

		 */

		__acpi_bus_get_power(device, &device->power.state);

	}



	return __acpi_bus_set_power(device, state);

}

EXPORT_SYMBOL(acpi_bus_set_power);
@@ -389,6 +398,29 @@ int acpi_bus_init_power(struct acpi_device *device) 
}





int acpi_bus_update_power(acpi_handle handle, int *state_p)

{

	struct acpi_device *device;

	int state;

	int result;



	result = acpi_bus_get_device(handle, &device);

	if (result)

		return result;



	result = __acpi_bus_get_power(device, &state);

	if (result)

		return result;



	result = __acpi_bus_set_power(device, state);

	if (!result && state_p)

		*state_p = state;



	return result;

}

EXPORT_SYMBOL_GPL(acpi_bus_update_power);





bool acpi_bus_power_manageable(acpi_handle handle)

{

	struct acpi_device *device;

include/acpi/acpi_bus.h

+1 −0
Original line number Diff line number Diff line
@@ -330,6 +330,7 @@ acpi_status acpi_bus_get_status_handle(acpi_handle handle, 
int acpi_bus_get_status(struct acpi_device *device);

int acpi_bus_get_power(acpi_handle handle, int *state);

int acpi_bus_set_power(acpi_handle handle, int state);

int acpi_bus_update_power(acpi_handle handle, int *state_p);

bool acpi_bus_power_manageable(acpi_handle handle);

bool acpi_bus_can_wakeup(acpi_handle handle);

#ifdef CONFIG_ACPI_PROC_EVENT

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