As mentioned in Calling VideoPortXxx from HwVidFindAdapter, a miniport driver’s HwVidFindAdapter function can request that configuration information be retrieved from the registry by calling either (or both) VideoPortGetDeviceData or VideoPortGetRegistryParameters with a driver-supplied HwVid..Callback function.
Each of the preceding VideoPortGetXxx functions retrieves information from a different key in the registry. Consequently, each requires the miniport driver to supply a system-defined HwVid..Callback function with different formal parameters. However, neither of the HwVid..Callbacks can retrieve configuration information about display driver defaults from the registry.
For more detailed information about parameters for the HwVidQueryDeviceCallback and HwVidQueryNamedValueCallback functions, see the Graphics Driver Reference.
A miniport driver also can call VideoPortSetRegistryParameters to store information, such as information about the DAC type, chip information, memory on adapter, and adapter identification information, in the registry under the key ..\CurrentControlSet\Services\DriverName\DeviceNumber.. For more information on storing hardware information in the registry, see Setting Hardware Information in the Registry. To retrieve the information from the registry later, the miniport calls VideoPortGetRegistryParameters.
Note that the registry information made available by calls to VideoPortGetDeviceData is volatile: it is re-created every time the system is loaded. Note also that the port driver makes this information and the configuration information returned by VideoPortGetRegistryParameters available only to video miniport drivers. A miniport driver cannot call VideoPortSetRegistryParameters to pass configuration information to its corresponding display driver.