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Failing a System Query-Power IRP in a Filter or Function Driver

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A filter or function driver (that is not the power policy owner for a device) can fail an IRP_MN_QUERY_POWER request if either of the following is true:

  • The device is enabled for wake-up and the requested system power state is less powered than the value of SystemWake, which specifies the least-powered state from which the device can wake the system. For example, a device that can wake the system from S2 but not from S3 would fail a query for S3 but succeed a query for S2.

  • Entering a device power state that corresponds to the requested state would force the driver to abandon an operation that would lose data, such as an open modem connection. A driver rarely will fail a query for this reason; under most circumstances, the application handles such cases.

To fail an IRP_MN_QUERY_POWER request for a system power state, a driver should take the following steps:

  1. Call PoStartNextPowerIrp to indicate that the driver is prepared to handle the next power IRP. (Windows Server 2003, Windows XP, and Windows 2000 only)

  2. Set Irp->IoStatus.Status to a failure status and call IoCompleteRequest, specifying IO_NO_INCREMENT. Do not pass the IRP further down the device stack.

  3. Call IoReleaseRemoveLock to release the previously acquired lock.

  4. Return a failure status from its DispatchPower routine.