IRP_MN_DISABLE_COLLECTION
Any WMI driver that registers one or more of its data blocks as expensive to collect must handle this IRP. A driver can handle WMI IRPs either by calling WmiSystemControl or by handling the IRP itself, as described in Handling WMI Requests.
If a driver calls WmiSystemControl to handle an IRP_MN_DISABLE_COLLECTION request, WMI in turn calls that driver's DpWmiFunctionControl routine.
Major Code
When Sent
WMI sends this IRP to request the driver to stop accumulating data for a data block that the driver registered as expensive to collect and for which data collection has been enabled.
WMI sends this IRP at IRQL = PASSIVE_LEVEL in an arbitrary thread context.
Input Parameters
Parameters.WMI.ProviderId points to the device object of the driver that should respond to the request. This pointer is located in the driver's I/O stack location in the IRP.
Parameters.WMI.DataPath points to a GUID that identifies the data block for which data accumulation should be stopped.
Output Parameters
None.
I/O Status Block
If the driver handles the IRP by calling WmiSystemControl, WMI sets Irp->IoStatus.Status and Irp->IoStatus.Information in the I/O status block.
Otherwise, the driver sets Irp->IoStatus.Status to STATUS_SUCCESS or to an appropriate error status such as the following:
STATUS_WMI_GUID_NOT_FOUND
STATUS_INVALID_DEVICE_REQUEST
On success, a driver sets Irp->IoStatus.Information to zero.
Operation
A driver registers a data block as expensive to collect by setting WMIREG_FLAG_EXPENSIVE in the Flags member of the WMIREGGUID or WMIGUIDREGINFO structure that the driver passes to WMI when it registers or updates the data block. A driver need not accumulate data for such a block until it receives an explicit request to enable collection.
If a driver handles WMI IRPs by calling WmiSystemControl, that routine calls the driver's DpWmiFunctionControl routine, or returns STATUS_SUCCESS if the driver does not define the routine.
If a driver handles an IRP_MN_DISABLE_COLLECTION request itself, it should do so only if Parameters.WMI.ProviderId points to the same device object as the pointer that the driver passed to IoWMIRegistrationControl. Otherwise, the driver must forward the request to the next-lower driver.
Before handling the request, the driver must determine whether Parameters.WMI.DataPath points to a GUID that the driver supports. If not, the driver must fail the IRP and return STATUS_WMI_GUID_NOT_FOUND. If the data block is valid but was not registered with WMIREG_FLAG_EXPENSIVE, the driver can return STATUS_SUCCESS and take no further action.
It is unnecessary for the driver to check whether data collection is already disabled because WMI sends a single disable request for the data block when the last data consumer disables collection for that block. WMI will not send another disable request without an intervening request to enable.
Requirements
Header |
Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h) |