/**
* acpi_device_get_power - Get power state of an ACPI device.
* @device: Device to get the power state of.
* @state: Place to store the power state of the device.
*
* This function does not update the device's power.state field, but it may
* update its parent's power.state field (when the parent's power state is
* unknown and the device's power state turns out to be D0).
*/
int acpi_device_get_power(struct acpi_device *device, int *state)
{
int result = ACPI_STATE_UNKNOWN;
if (!device || !state)
return -EINVAL;
if (!device->flags.power_manageable) {
/* TBD: Non-recursive algorithm for walking up hierarchy. */
*state = device->parent ?
device->parent->power.state : ACPI_STATE_D0;
goto out;
}
/*
* Get the device's power state either directly (via _PSC) or
* indirectly (via power resources).
*/
if (device->power.flags.explicit_get) {
unsigned long long psc;
acpi_status status = acpi_evaluate_integer(device->handle,
"_PSC", NULL, &psc);
if (ACPI_FAILURE(status))
return -ENODEV;
result = psc;
}
/* The test below covers ACPI_STATE_UNKNOWN too. */
if (result <= ACPI_STATE_D2) {
; /* Do nothing. */
} else if (device->power.flags.power_resources) {
int error = acpi_power_get_inferred_state(device, &result);
if (error)
return error;
} else if (result == ACPI_STATE_D3_HOT) {
result = ACPI_STATE_D3;
}
/*
* If we were unsure about the device parent's power state up to this
* point, the fact that the device is in D0 implies that the parent has
* to be in D0 too.
*/
if (device->parent && device->parent->power.state == ACPI_STATE_UNKNOWN
&& result == ACPI_STATE_D0)
device->parent->power.state = ACPI_STATE_D0;
*state = result;
out:
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",
device->pnp.bus_id, acpi_power_state_string(*state)));
return 0;
}
/**
* acpi_device_get_power - Get power state of an ACPI device.
* @device: Device to get the power state of.
* @state: Place to store the power state of the device.
*
* This function does not update the device's power.state field, but it may
* update its parent's power.state field (when the parent's power state is
* unknown and the device's power state turns out to be D0).
*/
int acpi_device_get_power(struct acpi_device *device, int *state)
{
int result = ACPI_STATE_UNKNOWN;
if (!device || !state)
return -EINVAL;
if (!device->flags.power_manageable) {
/* TBD: Non-recursive algorithm for walking up hierarchy. */
*state = device->parent ?
device->parent->power.state : ACPI_STATE_D0;
goto out;
}
/*
* Get the device's power state from power resources settings and _PSC,
* if available.
*/
if (device->power.flags.power_resources) {
int error = acpi_power_get_inferred_state(device, &result);
if (error)
return error;
}
if (device->power.flags.explicit_get) {
acpi_handle handle = device->handle;
unsigned long long psc;
acpi_status status;
status = acpi_evaluate_integer(handle, "_PSC", NULL, &psc);
if (ACPI_FAILURE(status))
return -ENODEV;
/*
* The power resources settings may indicate a power state
* shallower than the actual power state of the device.
*
* Moreover, on systems predating ACPI 4.0, if the device
* doesn't depend on any power resources and _PSC returns 3,
* that means "power off". We need to maintain compatibility
* with those systems.
*/
if (psc > result && psc < ACPI_STATE_D3_COLD)
result = psc;
else if (result == ACPI_STATE_UNKNOWN)
result = psc > ACPI_STATE_D2 ? ACPI_STATE_D3_COLD : psc;
}
/*
* If we were unsure about the device parent's power state up to this
* point, the fact that the device is in D0 implies that the parent has
* to be in D0 too, except if ignore_parent is set.
*/
if (!device->power.flags.ignore_parent && device->parent
&& device->parent->power.state == ACPI_STATE_UNKNOWN
&& result == ACPI_STATE_D0)
device->parent->power.state = ACPI_STATE_D0;
*state = result;
out:
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",
device->pnp.bus_id, acpi_power_state_string(*state)));
return 0;
}
/**
* acpi_device_set_power - Set power state of an ACPI device.
* @device: Device to set the power state of.
* @state: New power state to set.
*
* Callers must ensure that the device is power manageable before using this
* function.
*/
int acpi_device_set_power(struct acpi_device *device, int state)
{
int result = 0;
bool cut_power = false;
if (!device || !device->flags.power_manageable
|| (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
return -EINVAL;
/* Make sure this is a valid target state */
if (state == device->power.state) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already in %s\n",
device->pnp.bus_id,
acpi_power_state_string(state)));
return 0;
}
if (!device->power.states[state].flags.valid) {
dev_warn(&device->dev, "Power state %s not supported\n",
acpi_power_state_string(state));
return -ENODEV;
}
if (!device->power.flags.ignore_parent &&
device->parent && (state < device->parent->power.state)) {
dev_warn(&device->dev,
"Cannot transition to power state %s for parent in %s\n",
acpi_power_state_string(state),
acpi_power_state_string(device->parent->power.state));
return -ENODEV;
}
/* For D3cold we should first transition into D3hot. */
if (state == ACPI_STATE_D3_COLD
&& device->power.states[ACPI_STATE_D3_COLD].flags.os_accessible) {
state = ACPI_STATE_D3_HOT;
cut_power = true;
}
if (state < device->power.state && state != ACPI_STATE_D0
&& device->power.state >= ACPI_STATE_D3_HOT) {
dev_warn(&device->dev,
"Cannot transition to non-D0 state from D3\n");
return -ENODEV;
}
/*
* Transition Power
* ----------------
* In accordance with the ACPI specification first apply power (via
* power resources) and then evaluate _PSx.
*/
if (device->power.flags.power_resources) {
result = acpi_power_transition(device, state);
if (result)
goto end;
}
result = acpi_dev_pm_explicit_set(device, state);
if (result)
goto end;
if (cut_power) {
device->power.state = state;
state = ACPI_STATE_D3_COLD;
result = acpi_power_transition(device, state);
}
end:
if (result) {
dev_warn(&device->dev, "Failed to change power state to %s\n",
acpi_power_state_string(state));
} else {
device->power.state = state;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Device [%s] transitioned to %s\n",
device->pnp.bus_id,
acpi_power_state_string(state)));
}
return result;
}
/**
* acpi_device_set_power - Set power state of an ACPI device.
* @device: Device to set the power state of.
* @state: New power state to set.
*
* Callers must ensure that the device is power manageable before using this
* function.
*/
int acpi_device_set_power(struct acpi_device *device, int state)
{
int target_state = state;
int result = 0;
if (!device || !device->flags.power_manageable
|| (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
return -EINVAL;
/* Make sure this is a valid target state */
if (state == device->power.state) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already in %s\n",
device->pnp.bus_id,
acpi_power_state_string(state)));
return 0;
}
if (state == ACPI_STATE_D3_COLD) {
/*
* For transitions to D3cold we need to execute _PS3 and then
* possibly drop references to the power resources in use.
*/
state = ACPI_STATE_D3_HOT;
/* If _PR3 is not available, use D3hot as the target state. */
if (!device->power.states[ACPI_STATE_D3_COLD].flags.valid)
target_state = state;
} else if (!device->power.states[state].flags.valid) {
dev_warn(&device->dev, "Power state %s not supported\n",
acpi_power_state_string(state));
return -ENODEV;
}
if (!device->power.flags.ignore_parent &&
device->parent && (state < device->parent->power.state)) {
dev_warn(&device->dev,
"Cannot transition to power state %s for parent in %s\n",
acpi_power_state_string(state),
acpi_power_state_string(device->parent->power.state));
return -ENODEV;
}
/*
* Transition Power
* ----------------
* In accordance with ACPI 6, _PSx is executed before manipulating power
* resources, unless the target state is D0, in which case _PS0 is
* supposed to be executed after turning the power resources on.
*/
if (state > ACPI_STATE_D0) {
/*
* According to ACPI 6, devices cannot go from lower-power
* (deeper) states to higher-power (shallower) states.
*/
if (state < device->power.state) {
dev_warn(&device->dev, "Cannot transition from %s to %s\n",
acpi_power_state_string(device->power.state),
acpi_power_state_string(state));
return -ENODEV;
}
result = acpi_dev_pm_explicit_set(device, state);
if (result)
goto end;
if (device->power.flags.power_resources)
result = acpi_power_transition(device, target_state);
} else {
if (device->power.flags.power_resources) {
result = acpi_power_transition(device, ACPI_STATE_D0);
if (result)
goto end;
}
result = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
}
end:
if (result) {
dev_warn(&device->dev, "Failed to change power state to %s\n",
acpi_power_state_string(state));
} else {
device->power.state = target_state;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Device [%s] transitioned to %s\n",
device->pnp.bus_id,
acpi_power_state_string(state)));
}
return result;
}
/**
* acpi_device_set_power - Set power state of an ACPI device.
* @device: Device to set the power state of.
* @state: New power state to set.
*
* Callers must ensure that the device is power manageable before using this
* function.
*/
int acpi_device_set_power(struct acpi_device *device, int state)
{
int result = 0;
bool cut_power = false;
if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
return -EINVAL;
/* Make sure this is a valid target state */
if (state == device->power.state) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at %s\n",
acpi_power_state_string(state)));
return 0;
}
if (!device->power.states[state].flags.valid) {
printk(KERN_WARNING PREFIX "Device does not support %s\n",
acpi_power_state_string(state));
return -ENODEV;
}
if (device->parent && (state < device->parent->power.state)) {
printk(KERN_WARNING PREFIX
"Cannot set device to a higher-powered"
" state than parent\n");
return -ENODEV;
}
/* For D3cold we should first transition into D3hot. */
if (state == ACPI_STATE_D3_COLD
&& device->power.states[ACPI_STATE_D3_COLD].flags.os_accessible) {
state = ACPI_STATE_D3_HOT;
cut_power = true;
}
if (state < device->power.state && state != ACPI_STATE_D0
&& device->power.state >= ACPI_STATE_D3_HOT) {
printk(KERN_WARNING PREFIX
"Cannot transition to non-D0 state from D3\n");
return -ENODEV;
}
/*
* Transition Power
* ----------------
* In accordance with the ACPI specification first apply power (via
* power resources) and then evalute _PSx.
*/
if (device->power.flags.power_resources) {
result = acpi_power_transition(device, state);
if (result)
goto end;
}
result = acpi_dev_pm_explicit_set(device, state);
if (result)
goto end;
if (cut_power) {
device->power.state = state;
state = ACPI_STATE_D3_COLD;
result = acpi_power_transition(device, state);
}
end:
if (result) {
printk(KERN_WARNING PREFIX
"Device [%s] failed to transition to %s\n",
device->pnp.bus_id,
acpi_power_state_string(state));
} else {
device->power.state = state;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Device [%s] transitioned to %s\n",
device->pnp.bus_id,
acpi_power_state_string(state)));
}
return result;
}