Intel Extensible Firmware Interface - Manual (Page 150)

Extensible Firmware Interface Specification
5-52 12/01/02 Version 1.10
TEST_PROTOCOL Used by a driver to test for the existence of a protocol interface
on a handle.
Interface is optional for this attribute value, so
it is ignored, and the caller should only use the return status
code. The caller is also not required to close the protocol
interface with
CloseProtocol() .
BY_CHILD_CONTROLLER Used by bus drivers to show that a protocol interface is being
used by one of the child controllers of a bus. This information is
used by the boot service
ConnectController() to
recursively connect all child controllers and by the boot service
DisconnectController() to get the list of child
controllers that a bus driver created.
BY_DRIVER Used by a driver to gain access to a protocol interface. When
this mode is used, the driver’s
Stop() function will be called
by DisconnectController() if the protocol interface is
reinstalled or uninstalled. Once a protocol interface is opened by
a driver with this attribute, no other drivers will be allowed to
open the same protocol interface with the
BY_DRIVER attribute.
BY_DRIVER|EXCLUSIVE Used by a driver to gain exclusive access to a protocol interface.
If any other drivers have the protocol interface opened with an
attribute of
BY_DRIVER , then an attempt will be made to
remove them with DisconnectController() .
EXCLUSIVE Used by applications to gain exclusive access to a protocol
interface. If any drivers have the protocol interface opened with
an attribute of
BY_DRIVER , then an attempt will be made to
remove them by calling the driver’s Stop() function.
Status Codes Returned
EFI_SUCCESS An item was added to the open list for the protocol interface, and the
protocol interface was returned in
Interface .
EFI_INVALID_PARAMETER Protocol is NULL .
EFI_INVALID_PARAMETER Interface is NULL , and Attributes is not
TEST_PROTOCOL .
EFI_INVALID_PARAMETER Handle is not a valid EFI_HANDLE .
EFI_UNSUPPORTED Handle does not support Protocol .
EFI_INVALID_PARAMETER Attributes is not a legal value.
EFI_INVALID_PARAMETER Attributes is BY_CHILD_CONTROLLER and
AgentHandle is not a valid EFI_HANDLE .
EFI_INVALID_PARAMETER Attributes is BY_DRIVER and AgentHandle is not a valid
EFI_HANDLE .
EFI_INVALID_PARAMETER Attributes is BY_DRIVER|EXCLUSIVE and
AgentHandle is not a valid EFI_HANDLE .
continued