IoGetDeviceProperty function

The IoGetDeviceProperty routine retrieves information about a device such as configuration information and the name of its PDO.

Syntax

NTSTATUS IoGetDeviceProperty(
  PDEVICE_OBJECT           DeviceObject,
  DEVICE_REGISTRY_PROPERTY DeviceProperty,
  ULONG                    BufferLength,
  PVOID                    PropertyBuffer,
  PULONG                   ResultLength
);

Parameters

DeviceObject

Pointer to the physical device object (PDO) for the device being queried.

DeviceProperty

Specifies the device property being requested. Must be one of the following DEVICE_REGISTRY_PROPERTY enumeration values:

DevicePropertyAddress

Requests the address of the device on the bus. PropertyBuffer points to a ULONG.

The interpretation of this address is bus-specific. The caller of this routine should call the routine again to request the DevicePropertyBusTypeGuid, or possibly the DevicePropertyLegacyBusType, so it can interpret the address. An address value of 0xFFFFFFFF indicates that the underlying bus driver did not supply a bus address for the device.

DevicePropertyBootConfiguration

Requests the hardware resources assigned to the device by the firmware, in raw form. PropertyBuffer points to a CM_RESOURCE_LIST structure.

DevicePropertyBootConfigurationTranslated

The hardware resources assigned to the device by the firmware, in translated form. PropertyBuffer points to a CM_RESOURCE_LIST structure.

DevicePropertyBusNumber

Requests the legacy bus number of the bus the device is connected to. PropertyBuffer points to a ULONG.

DevicePropertyBusTypeGuid

Requests the GUID for the bus that the device is connected to. The system-defined bus type GUIDs are listed in the Wdmguid.h header file. PropertyBuffer points to a GUID, which is a 16-byte structure that contains the GUID in binary form.

DevicePropertyClassGuid

Requests the GUID for the device's setup class. PropertyBuffer points to a NULL-terminated array of WCHAR. This routine returns the GUID in a string format as follows, where each "c" represents a hexadecimal character: {cccccccc-cccc-cccc-cccc-cccccccccccc}

DevicePropertyClassName

Requests the name of the device's setup class, in text format. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyCompatibleIDs

Requests the compatible IDs reported by the device. PropertyBuffer points to a REG_MULTI_SZ value.

DevicePropertyDeviceDescription

Requests a string describing the device, such as "Microsoft PS/2 Port Mouse", typically defined by the manufacturer. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyDriverKeyName

Requests the name of the driver-specific registry key. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyEnumeratorName

Requests the name of the enumerator for the device, such as "PCI" or "root". PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyFriendlyName

Requests a string that can be used to distinguish between two similar devices, typically defined by the class installer. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyHardwareID

Requests the hardware IDs provided by the device that identify the device. PropertyBuffer points to a REG_MULTI_SZ value.

DevicePropertyInstallState

Requests the device's installation state. The installation state is returned as a DEVICE_INSTALL_STATE enumeration value.

DevicePropertyLegacyBusType

Requests the bus type, such as PCIBus or PCMCIABus. PropertyBuffer points to an INTERFACE_TYPE enumeration value.

DevicePropertyLocationInformation

Requests information about the device's location on the bus; the interpretation of this information is bus-specific. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyManufacturer

Requests a string identifying the manufacturer of the device. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyPhysicalDeviceObjectName

Requests the name of the PDO for this device. PropertyBuffer points to a NULL-terminated WCHAR string.

DevicePropertyRemovalPolicy

Requests the device's current removal policy. The operating system uses this value as a hint to determine how the device is normally removed. The PropertyBuffer parameter points to a DEVICE_REMOVAL_POLICY enumeration value.

DevicePropertyUINumber

Requests a number associated with the device that can be displayed in the user interface. PropertyBuffer points to a ULONG value.

This number is typically a user-perceived slot number, such as a number printed next to the slot on the board, or some other number that makes locating the physical device easier for the user. If the device is on a bus that has no UI number convention, or if the bus driver for the device cannot determine the UI number, this value is 0xFFFFFFFF.

BufferLength

Specifies the size, in bytes, of the caller-supplied PropertyBuffer.

PropertyBuffer

Pointer to a caller-supplied buffer to receive the property information. The buffer can be allocated from pageable memory. The type of the buffer is determined by the DeviceProperty (see above).

ResultLength

Pointer to a ULONG to receive the size of the property information returned at PropertyBuffer. If IoGetDeviceProperty returns STATUS_BUFFER_TOO_SMALL, it sets this parameter to the required buffer length.

Return Value

IoGetDeviceProperty returns STATUS_SUCCESS if the call was successful. Possible error return values include the following.

Return code Description
STATUS_BUFFER_TOO_SMALL The buffer at PropertyBuffer was too small. ResultLength points to the required buffer length.
STATUS_INVALID_PARAMETER_2 The given DeviceProperty is not one of the properties handled by this routine.
STATUS_INVALID_DEVICE_REQUEST Possibly indicates that the given DeviceObject was not a valid PDO pointer.

Remarks

IoGetDeviceProperty retrieves device setup information from the registry. Use this routine, rather than accessing the registry directly, to insulate a driver from differences across platforms and from possible changes in the registry structure.

For many DeviceProperty requests, it can take two or more calls to IoGetDeviceProperty to determine the required BufferLength. The first call should use a best-guess value. If the return status is STATUS_BUFFER_TOO_SMALL, the driver should free its current buffer, allocate a buffer of the size returned in ResultLength, and call IoGetDeviceProperty again. Because some of the setup properties are dynamic, the data size can change between the time the required size is returned and driver calls this routine again. Therefore, drivers should call IoGetDeviceProperty inside a loop that runs until the return status is not STATUS_BUFFER_TOO_SMALL.

Function drivers that support devices on a legacy bus and a PnP bus can use the DevicePropertyBusNumber, DevicePropertyBusTypeGuid, and DevicePropertyLegacyBusType properties to distinguish between the buses.

Requirements

   
Minimum supported client Available starting with Windows 2000.
Target Platform Universal
Header wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL PASSIVE_LEVEL
DDI compliance rules PowerIrpDDis, HwStorPortProhibitedDDIs

See Also

CM_RESOURCE_LIST

DEVICE_REMOVAL_POLICY

ExAllocatePoolWithTag

GUID

INTERFACE_TYPE

IO_RESOURCE_REQUIREMENTS_LIST