PoSetPowerState function (ntifs.h)
The PoSetPowerState routine notifies the system of a change in the device power state for a device.
Syntax
POWER_STATE PoSetPowerState(
[in] PDEVICE_OBJECT DeviceObject,
[in] POWER_STATE_TYPE Type,
[in] POWER_STATE State
);
Parameters
[in] DeviceObject
A pointer to the target DEVICE_OBJECT.
[in] Type
Indicates a POWER_STATE_TYPE value. Drivers must specify DevicePowerState.
[in] State
Specifies the power state to be set. Drivers must specify a DEVICE_POWER_STATE value.
Return value
PoSetPowerState returns the previous power state.
Remarks
PoSetPowerState notifies the power manager of the new power state for a device. Each driver in a device stack (filter, function, and bus drivers) must call PoSetPowerState to inform the power manager of a change in the power state of its corresponding device object. For example:
A driver calls this routine after receiving a device set-power request and before calling PoStartNextPowerIrp. When handling a PnP IRP_MN_START_DEVICE request, the driver should call PoSetPowerState to notify the power manager that the device is in the D0 state.
If the device is powering down, the driver must call PoSetPowerState before leaving the D0 state. In addition, the driver must be able to process client requests before PoSetPowerState returns.
If the device is powering up, the driver must call PoSetPowerState after the device is successfully put into the D0 state.
For more information about powering a device up and down, see Handling IRP_MN_SET_POWER for Device Power States.
Callers of PoSetPowerState must be running at IRQL <= APC_LEVEL except when setting state to D0. When setting state to D0, callers can be running at IRQL <= DISPATCH_LEVEL.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 |
| Target Platform | Universal |
| Header | ntifs.h (include Wdm.h, Ntddk.h, Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | See Remarks section. |