IWDFUsbTargetDevice::RetrievePowerPolicy method (wudfusb.h)

[Warning: UMDF 2 is the latest version of UMDF and supersedes UMDF 1. All new UMDF drivers should be written using UMDF 2. No new features are being added to UMDF 1 and there is limited support for UMDF 1 on newer versions of Windows 10. Universal Windows drivers must use UMDF 2. For more info, see Getting Started with UMDF.]

The RetrievePowerPolicy method retrieves a WinUsb power policy.

Syntax

HRESULT RetrievePowerPolicy(
  [in]      ULONG PolicyType,
  [in, out] ULONG *ValueLength,
  [out]     PVOID Value
);

Parameters

[in] PolicyType

The type of WinUsb power policy that the UMDF driver requests.

[in, out] ValueLength

A pointer to a variable that, on input, contains the size, in bytes, of the buffer that RetrievePowerPolicy supplies in Value. On output, this parameter contains the size that RetrievePowerPolicy requires for Value.

[out] Value

A pointer that receives the buffer that contains the WinUsb power policy.

Return value

RetrievePowerPolicy returns one of the following values:

Remarks

Power policy controls the power management that WinUsb for the device performs.

For information about valid policy types that a UMDF driver can pass for the PolicyType parameter and values that the framework returns, see the WinUsb_GetPowerPolicy function.

For more information about the power behavior of WinUSB, see WinUSB Power Management.

The RetrievePowerPolicy method generates a UMDF request and synchronously sends the request to the I/O target.

Requirements

See also

IWDFUsbTargetDevice

IWDFUsbTargetDevice::SetPowerPolicy

WinUsb_GetPowerPolicy