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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: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Rafael J. Wysocki 2010-11-25 00:09:15 +01:00 committed by Len Brown
parent ade3e7fef7
commit 25eed40720
2 changed files with 62 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

90
drivers/acpi/bus.c
View File

@ -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;

1
include/acpi/acpi_bus.h
View File

@ -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