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PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE structure (pep_x.h)

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The PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE structure contains an enumeration of the objects in the namespace of the device.

Syntax

typedef struct _PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE {
  PEPHANDLE                      DeviceHandle;
  ULONG                          RequestFlags;
  NTSTATUS                       Status;
  ULONG                          ObjectCount;
  SIZE_T                         ObjectBufferSize;
  PEP_ACPI_OBJECT_NAME_WITH_TYPE Objects[ANYSIZE_ARRAY];
} PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE, *PPEP_ACPI_ENUMERATE_DEVICE_NAMESPACE;

Members

DeviceHandle

A PEPHANDLE value that identifies the device's registration for ACPI services. The platform extension plug-in (PEP) supplied this handle in response to a previous PEP_NOTIFY_ACPI_REGISTER_DEVICE notification.

RequestFlags

A set of input flags. No flags are currently defined for this member, which is always set to PEP_ACPI_EDN_FLAG_NONE (0x0).

Status

An NTSTATUS value that indicates the status of the requested device-namespace enumeration. Set this member to STATUS_SUCCESS if the PEP succeeds in enumerating the objects in the device namespace. Set to STATUS_BUFFER_TOO_SMALL if the input value in the ObjectBufferSize member indicates that the allocated buffer is not large enough to contain the Objects array.

ObjectCount

The number of elements in the Objects array.

ObjectBufferSize

The size, in bytes, of the buffer that the Windows power management framework (PoFx) allocated for the Objects array elements that follow the structure. If the input value of ObjectBufferSize is not large enough to contain all the Objects array elements, the PEP overwrites the input value with the required size and sets the Status member to STATUS_BUFFER_TOO_SMALL. For more information, see Remarks.

Objects[ANYSIZE_ARRAY]

The first element in an array of PEP_ACPI_OBJECT_NAME_WITH_TYPE structures that describe the objects in the ACPI namespace of the device. If this array contains more than one element, the additional array elements follow the end of the PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE structure.

Remarks

This structure is used by the PEP_NOTIFY_ACPI_ENUMERATE_DEVICE_NAMESPACE notification. The RequestFlags and ObjectBufferSize members contain input values supplied by PoFx when the notification is sent. The PEP may overwrite the ObjectBufferSize input value with an output value if the input value is less than the required output buffer size. The Status, ObjectCount, and Objects members contain output values that the PEP writes to the structure.

ObjectCount is the number of objects listed in the ACPI namespace under this device. The PEP should verify that the storage allocated by PoFx for the Objects array is large enough to contain ObjectCount array elements. If ObjectCount > 1, the additional ObjectCount–1 array elements follow the end of the PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE structure. The buffer size required to contain the structure and additional array elements is calculated as follows:

sizeof(PEP_ACPI_ENUMERATE_DEVICE_NAMESPACE) + ((ObjectCount-1) * sizeof(PEP_ACPI_OBJECT_NAME_WITH_TYPE));

If the input value specified in the ObjectBufferSize member is less than the required size, the PEP overwrites the ObjectBufferSize input value with the required size, and sets the Status member to STATUS_BUFFER_TOO_SMALL. In response, PoFx will allocate a buffer of the required size and send a second PEP_NOTIFY_ACPI_ENUMERATE_DEVICE_NAMESPACE notification to the PEP for this device.

Requirements

Requirement Value
Minimum supported client Supported starting with Windows 10.
Header pep_x.h (include Pep_x.h)

See also