X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=MdePkg%2FInclude%2FProtocol%2FVariableWrite.h;h=d8d81076dc5b0a8bbb6283fe8ecf5c334764894c;hb=34860f7a069641fb9e14077c01605215aae68a9b;hp=cb8050eb0d942aaf8ace76a9c30b0540b52dec5f;hpb=0f82bd55142af193e669e76fcaf02f8d835f3f39;p=mirror_edk2.git

diff --git a/MdePkg/Include/Protocol/VariableWrite.h b/MdePkg/Include/Protocol/VariableWrite.h
index cb8050eb0d..d8d81076dc 100644
--- a/MdePkg/Include/Protocol/VariableWrite.h
+++ b/MdePkg/Include/Protocol/VariableWrite.h
@@ -1,13 +1,25 @@
 /** @file
   Variable Write Architectural Protocol as defined in PI Specification VOLUME 2 DXE
 
-  This code is used to produce the UEFI 2.0 runtime variable services
-
-  The SetVariable () UEFI 2.0 services may be updated to the EFI system table and the 
-  EFI_VARIABLE_WRITE_ARCH_PROTOCOL_GUID protocol is registered with a NULL pointer.
-
-  No CRC of the EFI system table is required, as it is done in the DXE core.
-
+  This provides the services required to set nonvolatile environment variables. 
+  This protocol must be produced by a runtime DXE driver and may be consumed only 
+  by the DXE Foundation.
+
+  The DXE driver that produces this protocol must be a runtime driver. This driver 
+  may update the SetVariable() field of the UEFI Runtime Services Table.
+  
+  After the UEFI Runtime Services Table has been initialized, the driver must 
+  install the EFI_VARIABLE_WRITE_ARCH_PROTOCOL_GUID on a new handle with a NULL 
+  interface pointer. The installation of this protocol informs the DXE Foundation 
+  that the write services for nonvolatile environment variables are now available 
+  and that the DXE Foundation must update the 32-bit CRC of the UEFI Runtime Services 
+  Table. The full complement of environment variable services are not available 
+  until both this protocol and EFI_VARIABLE_ARCH_PROTOCOL are installed. DXE drivers 
+  that require read-only access or read/write access to volatile environment variables
+  must have the EFI_VARIABLE_WRITE_ARCH_PROTOCOL in their dependency expressions.
+  DXE drivers that require write access to nonvolatile environment variables must 
+  have this architectural protocol in their dependency expressions.  
+  
   Copyright (c) 2006 - 2008, Intel Corporation                                                         
   All rights reserved. This program and the accompanying materials                          
   are licensed and made available under the terms and conditions of the BSD License         
@@ -22,9 +34,9 @@
 #ifndef __ARCH_PROTOCOL_VARIABLE_WRITE_ARCH_H__
 #define __ARCH_PROTOCOL_VARIABLE_WRITE_ARCH_H__
 
-//
-// Global ID for the Variable Write Architectural Protocol
-//
+///
+/// Global ID for the Variable Write Architectural Protocol
+///
 #define EFI_VARIABLE_WRITE_ARCH_PROTOCOL_GUID \
   { 0x6441f818, 0x6362, 0x4e44, {0xb5, 0x70, 0x7d, 0xba, 0x31, 0xdd, 0x24, 0x53 } }