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ACPI: Add acpi_pm_device_sleep_state helper routine

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Based on the David Brownell's patch at
http://marc.info/?l=linux-acpi&m=117873972806360&w=2
updated by: Rafael J. Wysocki <rjw@sisk.pl>

Add a helper routine returning the lowest power (highest number) ACPI device
power state that given device can be in while the system is in the sleep state
indicated by acpi_target_sleep_state .

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Shaohua Li 2007-07-17 22:40:25 +02:00 committed by Len Brown
parent e9b3aba887
commit fd4aff1a28
2 changed files with 77 additions and 0 deletions
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75
drivers/acpi/sleep/main.c
View file

@ -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.

2
include/acpi/acpi_bus.h
View file

@ -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__*/