Intel Extensible Firmware Interface - Manual (Page 261)

Protocols — EFI Driver Model
Version 1.10 12/01/02 9-19
If ControllerHandle cannot be stopped, then EFI_DEVICE_ERROR is returned. If, for
some reason, there are not enough resources to stop ControllerHandle , then
EFI_OUT_OF_RESOURCES is returned. If ControllerHandle was not started by the driver
specified by This , then EFI_UNSUPPORTED is returned.
The Stop() function is designed to be invoked from the EFI boot service
DisconnectController() . As a result, much of the error checking on the parameters to
Stop() has been moved into this common boot service. It is legal to call Stop() from other
locations, but the following calling restrictions must be followed or the system behavior will not be
deterministic.
1. ControllerHandle must be a valid EFI_HANDLE that was used on a previous call to this
same driver’s Start() function.
2. The first NumberOfChildren handles of ChildHandleBuffer must all be a valid
EFI_HANDLE . In addition, all of these handles must have been created in this driver’s
Start() function, and the Start() function must have called OpenProtocol() on
ControllerHandle with an Attribute of
EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER .
Status Codes Returned
EFI_SUCCESS The device was stopped .
EFI_DEVICE_ERROR The device could not be stopped due to a device error.
Examples
extern EFI_GUID gEfiDriverBindingProtocolGuid;
EFI_HANDLE DriverImageHandle;
EFI_HANDLE ControllerHandle;
EFI_HANDLE ChildHandle;
EFI_DRIVER_BINDING_PROTOCOL *DriverBinding;
//
// Use the DriverImageHandle to get the Driver Binding Protocol instance
//
Status = gBS->OpenProtocol (
DriverImageHandle,
&gEfiDriverBindingProtocolGuid,
&DriverBinding,
DriverImageHandle,
NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Use the Driver Binding Protocol instance to free the child
// specified by ChildHandle. Then, use the Driver Binding
// Protocol to stop ControllerHandle.
//