ACPI: Add acpi_pm_device_sleep_state helper routine (fd4aff1a) · Commits · 戴 / test

drivers/acpi/sleep/main.c

+75 −0

Original line number	Diff line number	Diff line
		@@ -260,6 +260,81 @@ static struct hibernation_ops acpi_hibernation_ops = {
		};
		#endif /* CONFIG_SOFTWARE_SUSPEND */

		/**
		* acpi_pm_device_sleep_state - return preferred power state of ACPI device
		* in the system sleep state given by %acpi_target_sleep_state
		* @dev: device to examine
		* @wake: if set, the device should be able to wake up the system
		* @d_min_p: used to store the upper limit of allowed states range
		* Return value: preferred power state of the device on success, -ENODEV on
		* failure (ie. if there's no 'struct acpi_device' for @dev)
		*
		* Find the lowest power (highest number) ACPI device power state that
		* device @dev can be in while the system is in the sleep state represented
		* by %acpi_target_sleep_state. If @wake is nonzero, the device should be
		* able to wake up the system from this sleep state. If @d_min_p is set,
		* the highest power (lowest number) device power state of @dev allowed
		* in this system sleep state is stored at the location pointed to by it.
		*
		* The caller must ensure that @dev is valid before using this function.
		* The caller is also responsible for figuring out if the device is
		* supposed to be able to wake up the system and passing this information
		* via @wake.
		*/

		int acpi_pm_device_sleep_state(struct device dev, int wake, int d_min_p)
		{
		acpi_handle handle = DEVICE_ACPI_HANDLE(dev);
		struct acpi_device *adev;
		char acpi_method[] = "_SxD";
		unsigned long d_min, d_max;

		if (!handle \|\| ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
		printk(KERN_ERR "ACPI handle has no context!\n");
		return -ENODEV;
		}

		acpi_method[2] = '0' + acpi_target_sleep_state;
		/*
		* If the sleep state is S0, we will return D3, but if the device has
		* _S0W, we will use the value from _S0W
		*/
		d_min = ACPI_STATE_D0;
		d_max = ACPI_STATE_D3;

		/*
		* If present, _SxD methods return the minimum D-state (highest power
		* state) we can use for the corresponding S-states. Otherwise, the
		* minimum D-state is D0 (ACPI 3.x).
		*
		* NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
		* provided -- that's our fault recovery, we ignore retval.
		*/
		if (acpi_target_sleep_state > ACPI_STATE_S0)
		acpi_evaluate_integer(handle, acpi_method, NULL, &d_min);

		/*
		* If _PRW says we can wake up the system from the target sleep state,
		* the D-state returned by _SxD is sufficient for that (we assume a
		* wakeup-aware driver if wake is set). Still, if _SxW exists
		* (ACPI 3.x), it should return the maximum (lowest power) D-state that
		* can wake the system. _S0W may be valid, too.
		*/
		if (acpi_target_sleep_state == ACPI_STATE_S0 \|\|
		(wake && adev->wakeup.state.enabled &&
		adev->wakeup.sleep_state <= acpi_target_sleep_state)) {
		acpi_method[3] = 'W';
		acpi_evaluate_integer(handle, acpi_method, NULL, &d_max);
		/* Sanity check */
		if (d_max < d_min)
		d_min = d_max;
		}

		if (d_min_p)
		*d_min_p = d_min;
		return d_max;
		}

		/*
		* Toshiba fails to preserve interrupts over S1, reinitialization
		* of 8259 is needed after S1 resume.

include/acpi/acpi_bus.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -364,6 +364,8 @@ acpi_handle acpi_get_child(acpi_handle, acpi_integer);
		acpi_handle acpi_get_pci_rootbridge_handle(unsigned int, unsigned int);
		#define DEVICE_ACPI_HANDLE(dev) ((acpi_handle)((dev)->archdata.acpi_handle))

		int acpi_pm_device_sleep_state(struct device , int, int );

		#endif /* CONFIG_ACPI */

		#endif /__ACPI_BUS_H__/

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