PMINIPORT_GET_REGISTRY_ROUTINE callback function (video.h)

Article
04/01/2021

HwVidQueryNamedValueCallback processes the specified data retrieved from the registry.

Syntax

PMINIPORT_GET_REGISTRY_ROUTINE PminiportGetRegistryRoutine;

VP_STATUS PminiportGetRegistryRoutine(
  PVOID HwDeviceExtension,
  PVOID Context,
  PWSTR ValueName,
  PVOID ValueData,
  ULONG ValueLength
)
{...}

Parameters

HwDeviceExtension

Pointer to the miniport driver's per-adapter storage area. For more information, see Device Extensions.

Context

Pointer to a driver-determined context specified as input to the VideoPortGetRegistryParameters function.

ValueName

Pointer to a NULL-terminated Unicode string naming the entry.

ValueData

Pointer to the buffered data associated with ValueName, supplied by VideoPortGetRegistryParameters.

ValueLength

Specifies the size in bytes of the buffer at ValueData.

Return value

HwVidQueryNamedValueCallback returns the status of the operation.

Remarks

HwVidQueryNamedValueCallback is an optional miniport driver function passed in a call to VideoPortGetRegistryParameters.

VideoPortGetRegistryParameters calls HwVidQueryNamedValueCallback after collecting available configuration information about the given ValueName in the adapter key of the registry.

HwVidFindAdapter or HwVidInitialize can call VideoPortGetRegistryParameters with a driver-supplied HwVidQueryNamedValueCallback function, pointers to the device extension and any driver-supplied context data (which can be the VIDEO_PORT_CONFIG_INFO buffer), and a pointer to a Unicode string naming the value to be retrieved from the registry.

HwVidFindAdapter or HwVidInitialize can set VideoPortGetRegistryParameters's IsFileNameParameter argument to TRUE if the driver-supplied Unicode string is a named registry entry whose value is a file name. For this specification, the returned data will be the contents of the named file.

When VideoPortGetRegistryParameters calls the HwVidQueryNamedValueCallback function, it processes whatever configuration data is made available. For example, HwVidQueryNamedValueCallback might use retrieved data to determine the miniport driver's access ranges and to set up its emulator access ranges (if any), interrupt vector or interrupt IRQL (if any), and so forth in the VIDEO_PORT_CONFIG_INFO buffer, as well as in the miniport driver's device extension, before returning control to the HwVidFindAdapter function.

HwVidInitialize might also call VideoPortGetRegistryParameters with IsFileNameParameter set to TRUE so that the miniport driver-supplied HwVidQueryNamedValueCallback function could use the buffered contents of a named file to set up microcode on the adapter.

The returned ValueData is on the stack, so it can be referenced locally. HwVidQueryNamedValueCallback can store some or all of the returned information for use by other miniport driver functions in the input HwDeviceExtension or use the input Context as a pointer to a location where the data can be stored.

HwVidQueryNamedValueCallback should be made pageable.

Requirements

Requirement	Value
Target Platform	Desktop
Header	video.h (include Video.h)