diff --git a/MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c b/MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c
index aded0b3acb..3161ede949 100644
--- a/MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c
+++ b/MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c
@@ -1704,7 +1704,7 @@ EhcDriverBindingStart (
   }
 
   //
-  // Robustnesss improvement such as for UoL
+  // Robustnesss improvement such as for Duet platform
   // Default is not required.
   //
   if (FeaturePcdGet (PcdTurnOffUsbLegacySupport)) {
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index d14cf8b56b..51bafbb44e 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -219,7 +219,8 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdPeiCoreImageLoaderSearchTeSectionFirst|TRUE|BOOLEAN|0x00010044
 
   ## If TRUE, force to switch off the support of legacy usb. So legacy usb device driver can not make use of SMI
-  #  interrupt to access usb device in the case of absence of usb stack.
+  #  interrupt to access usb device in the case of absence of usb stack. 
+  #  DUET platform requires the token to be TRUE.
   gEfiMdeModulePkgTokenSpaceGuid.PcdTurnOffUsbLegacySupport|FALSE|BOOLEAN|0x00010047
 
   ## If TRUE, HiiImageProtocol will be installed.