DeviceName [in, optional]
Optionally points to a buffer containing a null-terminated Unicode string that names the device object. The string must be a full path name. WDM filter and function drivers do not name their device objects. For more information, see Named Device Objects.
Note If a device name is not supplied (that is, DeviceName is NULL), the device object created by IoCreateDevice will not (and cannot) have a discretionary access control list (DACL) associated with it. For additional information, see Security Descriptors.