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Enabling and Disabling a Device Interface Instance

After successfully starting the device, the driver that registered the interface calls IoSetDeviceInterfaceState to enable an interface instance. The driver passes the symbolic link name returned by IoRegisterDeviceInterface together with the Boolean value TRUE to enable the interface instance.

If the driver can successfully start its device, it should call this routine while handling the Plug and Play (PnP) manager's IRP_MN_START_DEVICE request.

After the IRP_MN_START_DEVICE request completes, the PnP manager issues device interface arrival notifications to any kernel-mode or user-mode components that requested them. For more information, see Registering for Device Interface Change Notification.

To disable a device interface instance, a driver calls IoSetDeviceInterfaceState, passing the SymbolicLinkName returned by IoRegisterDeviceInterface and FALSE as the value of Enable.

A driver should disable a device's interfaces when it handles an IRP_MN_SURPRISE_REMOVAL or IRP_MN_REMOVE_DEVICE request for the device. If a driver does not disable a device's interfaces when it handles these removal IRPs, it must not subsequently attempt to do this because the PnP manager will disable the interfaces when it removes the device.

A driver should not disable the interfaces when the device is stopped (IRP_MN_STOP_DEVICE); instead, it should leave any device interfaces enabled and queue I/O requests until it receives another IRP_MN_START_DEVICE request. Similarly, a driver should not disable its interfaces when the device is put in a sleep state. It should queue I/O requests until the device wakes up. For more information, see Supporting Devices that Have Wake-Up Capabilities.

 

 

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