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Intel Extensible Firmware Interface User Manual

Page 472

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Extensible Firmware Interface Specification

12-54

12/01/02

Version 1.10

The

Stop()

function mirrors the

Start()

function, so the

Stop()

function completes any

outstanding transactions to the PCI Controller and removes the protocol interfaces that were
installed in

Start()

. Figure 12-14 shows the device handle for a PCI Controller before and after

Start()

is called. In this example, a PCI Device Driver is adding the Block I/O Protocol to the

device handle for the PCI Controller. It is also a PCI Device Driver’s responsibility to disable the
I/O, Memory, and Bus Master decodes by calling

Attributes()

.

OM13168

PCI Controller Device Handle

EFI_DEVICE_PATH_PROTOCOL

EFI_PCI_I/O_PROTOCOL

EFI_BLOCK_I/O_PROTOCOL

PCI Controller Device Handle

EFI_DEVICE_PATH_PROTOCOL

EFI_PCI_I/O_PROTOCOL

Stop() : Closes PCI I/O

Start() : Opens PCI I/O

Installed by Start()

Uninstalled by Stop()

Figure 12-14. Connecting a PCI Device Driver