synchronize the files with the MDE_Library_Spec

[mirror_edk2.git] / MdePkg / Include / Library / PciLib.h

diff --git a/MdePkg/Include/Library/PciLib.h b/MdePkg/Include/Library/PciLib.h
index d76ecee7c045845cea3ed1d574868adc9169c59f..4e413aa9f136e043257834ac4a0b3d647447d3da 100644 (file)
--- a/MdePkg/Include/Library/PciLib.h
+++ b/MdePkg/Include/Library/PciLib.h
@@ -1,5 +1,14 @@
 /** @file\r
   Provides services to access PCI Configuration Space.\r
+  \r
+  These functions perform PCI configuration cycles using the default PCI configuration \r
+  access method. This may use I/O ports 0xCF8 and 0xCFC to perform PCI configuration accesses, \r
+  or it may use MMIO registers relative to the PcdPciExpressBaseAddress, or it may use some \r
+  alternate access method.  Modules will typically use the PCI Library for its PCI configuration \r
+  accesses.  However, if a module requires a mix of PCI access methods, the PCI CF8 Library or \r
+  PCI Express Library may be used in conjunction with the PCI Library.  The functionality of \r
+  these three libraries is identical.  The PCI CF8 Library and PCI Express Library simply use \r
+  explicit access methods.\r
 \r
 Copyright (c) 2006 - 2008, Intel Corporation\r
 All rights reserved. This program and the accompanying materials\r