Opening a device's software key

You must not directly open a device's software key. As with any registry key, the location or format of these keys might change between different versions of Windows.

Note

You should open a device's software key only after the corresponding device has been found. For more information about this procedure, see Enumerating Installed Devices.

To open or create a device's software key, follow these guidelines:

Note

You must set the parameter where you provide the requested security access to the minimal access permissions that are required. You must not set this parameter to KEY_ALL_ACCESS. For more information about how to specify access permissions for registry access, see Accessing Registry Keys Safely.

• To open an existing software key, use CM_Open_DevNode_Key with a Disposition of RegDisposition_OpenExisting and ulFlags containing CM_REGISTRY_SOFTWARE or use SetupDiOpenDevRegKey and KeyType parameter of DIREG_DRV.

• To create a software key, use CM_Open_DevNode_Key with a Disposition of RegDisposition_OpenAlways and ulFlags containing CM_REGISTRY_SOFTWARE or use SetupDiCreateDevRegKey and KeyType parameter of DIREG_DRV.

• Kernel-mode callers should use IoOpenDeviceRegistryKey and set the DevInstKeyType parameter to PLUGPLAY_REGKEY_DRIVER.

Modifying Registry Values in a Device's Software Key

You must not modify the values of the following registry entries (device properties) in a device's software key:

• DriverDate

• DriverDateData

• DriverDesc

• DriverVersion

• InfPath

• InfSection

• InfSectionExt

• MatchingDeviceId

• ProviderName

• EnumPropPages32

These device properties represent a device's installation state. Direct modification of these properties might invalidate the device's installation state. For example, changing information related to the INF file invalidates information about driver files that are associated with such properties as device and driver signing information. Changing driver version or driver date might break Windows Update functionality.

Note

Starting with Windows Vista, the operating system imposes "installation-time only" access restrictions for these properties. Values can be replicated for compatibility, and direct modification of values during device installation does not affect internal state.