X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=MdeModulePkg%2FBus%2FPci%2FPciBusDxe%2FPciEnumeratorSupport.c;h=6f3d1bebc6c298fbba88bffa660fff1b0f81fdd0;hp=81171c82d9e21500ceaf25464d78d196904b02b2;hb=d92336541782f9d51b6a6fb743e14d5ef754deeb;hpb=2b5f0daa6c5f1d205b82c52c9ce55307a1787a3e

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
index 81171c82d9..6f3d1bebc6 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
@@ -1,7 +1,7 @@
 /** @file
   PCI emumeration support functions implementation for PCI Bus module.
 
-Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
 (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
@@ -1254,9 +1254,11 @@ DetermineDeviceAttribute (
     PciSetDeviceAttribute (PciIoDevice, OldCommand, OldBridgeControl, EFI_SET_ATTRIBUTES);
 
     //
-    // Enable other supported attributes but not defined in PCI_IO_PROTOCOL
-    //
-    PCI_ENABLE_COMMAND_REGISTER (PciIoDevice, EFI_PCI_COMMAND_MEMORY_WRITE_AND_INVALIDATE);
+    // Enable other PCI supported attributes but not defined in PCI_IO_PROTOCOL
+    // For PCI Express devices, Memory Write and Invalidate is hardwired to 0b so only enable it for PCI devices.
+    if (!PciIoDevice->IsPciExp) {
+      PCI_ENABLE_COMMAND_REGISTER (PciIoDevice, EFI_PCI_COMMAND_MEMORY_WRITE_AND_INVALIDATE);
+    }
   }
 
   FastB2BSupport = TRUE;