diff --git a/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.c b/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.c
index b8e3ea460d..75cff37773 100644
--- a/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.c
+++ b/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.c
@@ -207,6 +207,9 @@ DoS3 (
                                 valid if ResetStatus is something other than EFI_SUCCESS
                                 unless the ResetType is EfiResetPlatformSpecific
                                 where a minimum amount of ResetData is always required.
+                                For a ResetType of EfiResetPlatformSpecific the data buffer
+                                also starts with a Null-terminated string that is followed
+                                by an EFI_GUID that describes the specific type of reset to perform.
 **/
 VOID
 EFIAPI
diff --git a/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.h b/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.h
index 73e657d4e0..75cdd88896 100644
--- a/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.h
+++ b/MdeModulePkg/Universal/ResetSystemRuntimeDxe/ResetSystem.h
@@ -75,10 +75,18 @@ InitializeResetSystem (
 
   @param[in] ResetType          The type of reset to perform.
   @param[in] ResetStatus        The status code for the reset.
-  @param[in] DataSize           The size, in bytes, of WatchdogData.
+  @param[in] DataSize           The size, in bytes, of ResetData.
   @param[in] ResetData          For a ResetType of EfiResetCold, EfiResetWarm, or
                                 EfiResetShutdown the data buffer starts with a Null-terminated
                                 string, optionally followed by additional binary data.
+                                The string is a description that the caller may use to further
+                                indicate the reason for the system reset. ResetData is only
+                                valid if ResetStatus is something other than EFI_SUCCESS
+                                unless the ResetType is EfiResetPlatformSpecific
+                                where a minimum amount of ResetData is always required.
+                                For a ResetType of EfiResetPlatformSpecific the data buffer
+                                also starts with a Null-terminated string that is followed
+                                by an EFI_GUID that describes the specific type of reset to perform.
 
 **/
 VOID