From 6a55eea3eba088eaaad7c7f1f14580016c37406b Mon Sep 17 00:00:00 2001
From: mdkinney <mdkinney@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Sat, 4 Dec 2010 20:05:09 +0000
Subject: [PATCH] Update PEI/DXE/SMM dispatchers to include DEBUG
 ((DEBUG_DISPATCH, )) macros to log the evaluation of all dependency
 expressions.

This logging can be enabled by setting the DEBUG_DISPATCH bit(0x80) of the PCD gEfiMdePkgTokenSpaceGuid.PcdDebugPrintErrorLevel.





git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11117 6f19259b-4bc3-4df7-8a09-765794883524
---
 MdeModulePkg/Core/Dxe/Dispatcher/Dependency.c | 38 ++++++++++++++++++-
 MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c | 32 +++++++++++++---
 MdeModulePkg/Core/Pei/Dependency/Dependency.c | 22 ++++++++++-
 MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c | 10 +++++
 MdeModulePkg/Core/PiSmmCore/Dependency.c      | 33 ++++++++++++++++
 MdeModulePkg/Core/PiSmmCore/Dispatcher.c      | 27 ++++++++++++-
 6 files changed, 153 insertions(+), 9 deletions(-)

diff --git a/MdeModulePkg/Core/Dxe/Dispatcher/Dependency.c b/MdeModulePkg/Core/Dxe/Dispatcher/Dependency.c
index 55eed231fd..0ec9690890 100644
--- a/MdeModulePkg/Core/Dxe/Dispatcher/Dependency.c
+++ b/MdeModulePkg/Core/Dxe/Dispatcher/Dependency.c
@@ -5,7 +5,7 @@
   if a driver can be scheduled for execution.  The criteria for
   schedulability is that the dependency expression is satisfied.
 
-Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
@@ -220,6 +220,8 @@ CoreIsSchedulable (
   EFI_GUID    DriverGuid;
   VOID        *Interface;
 
+  DEBUG ((DEBUG_DISPATCH, "Evaluate DXE DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+
   Operator = FALSE;
   Operator2 = FALSE;
 
@@ -236,9 +238,12 @@ CoreIsSchedulable (
     // A NULL Depex means treat the driver like an UEFI 2.0 thing.
     //
     Status = CoreAllEfiServicesAvailable ();
+    DEBUG ((DEBUG_DISPATCH, "  All UEFI Services Available                     = "));
     if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_DISPATCH, "FALSE\n  RESULT = FALSE\n"));
       return FALSE;
     }
+    DEBUG ((DEBUG_DISPATCH, "TRUE\n  RESULT = TRUE\n"));
     return TRUE;
   }
 
@@ -257,6 +262,7 @@ CoreIsSchedulable (
     // past the end of the dependency expression.
     //
     if (((UINTN)Iterator - (UINTN)DriverEntry->Depex) >= DriverEntry->DepexSize) {
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Attempt to fetch past end of depex)\n"));
       return FALSE;
     }
 
@@ -272,6 +278,7 @@ CoreIsSchedulable (
       // If the code flow arrives at this point, there was a BEFORE or AFTER
       // that were not the first opcodes.
       //
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected BEFORE or AFTER opcode)\n"));
       ASSERT (FALSE);
     case EFI_DEP_SOR:
       //
@@ -279,8 +286,11 @@ CoreIsSchedulable (
       // at any other location, then the dependency expression evaluates to FALSE
       //
       if (Iterator != DriverEntry->Depex) {
+        DEBUG ((DEBUG_DISPATCH, "  SOR\n"));
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected SOR opcode)\n"));
         return FALSE;
       }
+      DEBUG ((DEBUG_DISPATCH, "  SOR                                             = Requested\n"));
       //
       // Otherwise, it is the first opcode and should be treated as a NOP.
       //
@@ -296,12 +306,15 @@ CoreIsSchedulable (
       Status = CoreLocateProtocol (&DriverGuid, NULL, &Interface);
 
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = FALSE\n", &DriverGuid));
         Status = PushBool (FALSE);
       } else {
+        DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = TRUE\n", &DriverGuid));
         *Iterator = EFI_DEP_REPLACE_TRUE;
         Status = PushBool (TRUE);
       }
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
@@ -309,75 +322,97 @@ CoreIsSchedulable (
       break;
 
     case EFI_DEP_AND:
+      DEBUG ((DEBUG_DISPATCH, "  AND\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PopBool (&Operator2);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PushBool ((BOOLEAN)(Operator && Operator2));
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_OR:
+      DEBUG ((DEBUG_DISPATCH, "  OR\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PopBool (&Operator2);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PushBool ((BOOLEAN)(Operator || Operator2));
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_NOT:
+      DEBUG ((DEBUG_DISPATCH, "  NOT\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PushBool ((BOOLEAN)(!Operator));
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_TRUE:
+      DEBUG ((DEBUG_DISPATCH, "  TRUE\n"));
       Status = PushBool (TRUE);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_FALSE:
+      DEBUG ((DEBUG_DISPATCH, "  FALSE\n"));
       Status = PushBool (FALSE);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_END:
+      DEBUG ((DEBUG_DISPATCH, "  END\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = %a\n", Operator ? "TRUE" : "FALSE"));
       return Operator;
 
     case EFI_DEP_REPLACE_TRUE:
+      CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID));
+      DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = TRUE\n", &DriverGuid));
+      
       Status = PushBool (TRUE);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
@@ -385,6 +420,7 @@ CoreIsSchedulable (
       break;
 
     default:
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unknown opcode)\n"));
       goto Done;
     }
 
diff --git a/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c b/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c
index 9e06881c85..79b895bcfa 100644
--- a/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c
+++ b/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c
@@ -333,9 +333,14 @@ CoreSchedule (
       DriverEntry->Dependent    = TRUE;
       CoreReleaseDispatcherLock ();
 
+      DEBUG ((DEBUG_DISPATCH, "Schedule FFS(%g) - EFI_SUCCESS\n", DriverName));
+      
       return EFI_SUCCESS;
     }
   }
+  
+  DEBUG ((DEBUG_DISPATCH, "Schedule FFS(%g) - EFI_NOT_FOUND\n", DriverName));
+  
   return EFI_NOT_FOUND;
 }
 
@@ -572,6 +577,12 @@ CoreDispatcher (
           CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
           ReadyToRun = TRUE;
         }
+      } else {
+        if (DriverEntry->Unrequested) {
+          DEBUG ((DEBUG_DISPATCH, "Evaluate DXE DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+          DEBUG ((DEBUG_DISPATCH, "  SOR                                             = Not Requested\n"));
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE\n"));
+        }
       }
     }
   } while (ReadyToRun);
@@ -611,12 +622,17 @@ CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
   //
   for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
     DriverEntry = CR(Link, EFI_CORE_DRIVER_ENTRY, Link, EFI_CORE_DRIVER_ENTRY_SIGNATURE);
-    if (DriverEntry->Before && DriverEntry->Dependent) {
+    if (DriverEntry->Before && DriverEntry->Dependent && DriverEntry != InsertedDriverEntry) {
+      DEBUG ((DEBUG_DISPATCH, "Evaluate DXE DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+      DEBUG ((DEBUG_DISPATCH, "  BEFORE FFS(%g) = ", &DriverEntry->BeforeAfterGuid));
       if (CompareGuid (&InsertedDriverEntry->FileName, &DriverEntry->BeforeAfterGuid)) {
         //
         // Recursively process BEFORE
         //
+        DEBUG ((DEBUG_DISPATCH, "TRUE\n  END\n  RESULT = TRUE\n"));
         CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
+      } else {
+        DEBUG ((DEBUG_DISPATCH, "FALSE\n  END\n  RESULT = FALSE\n"));
       }
     }
   }
@@ -637,12 +653,17 @@ CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
   //
   for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
     DriverEntry = CR(Link, EFI_CORE_DRIVER_ENTRY, Link, EFI_CORE_DRIVER_ENTRY_SIGNATURE);
-    if (DriverEntry->After && DriverEntry->Dependent) {
+    if (DriverEntry->After && DriverEntry->Dependent && DriverEntry != InsertedDriverEntry) {
+      DEBUG ((DEBUG_DISPATCH, "Evaluate DXE DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+      DEBUG ((DEBUG_DISPATCH, "  AFTER FFS(%g) = ", &DriverEntry->BeforeAfterGuid));
       if (CompareGuid (&InsertedDriverEntry->FileName, &DriverEntry->BeforeAfterGuid)) {
         //
         // Recursively process AFTER
         //
+        DEBUG ((DEBUG_DISPATCH, "TRUE\n  END\n  RESULT = TRUE\n"));
         CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
+      } else {
+        DEBUG ((DEBUG_DISPATCH, "FALSE\n  END\n  RESULT = FALSE\n"));
       }
     }
   }
@@ -1139,23 +1160,24 @@ CoreFwVolEventProtocolNotify (
     // drivers not in the current FV and these must be skipped since the a priori list
     // is only valid for the FV that it resided in.
     //
-    CoreAcquireDispatcherLock ();
 
     for (Index = 0; Index < AprioriEntryCount; Index++) {
       for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
         DriverEntry = CR(Link, EFI_CORE_DRIVER_ENTRY, Link, EFI_CORE_DRIVER_ENTRY_SIGNATURE);
         if (CompareGuid (&DriverEntry->FileName, &AprioriFile[Index]) &&
             (FvHandle == DriverEntry->FvHandle)) {
+          CoreAcquireDispatcherLock ();
           DriverEntry->Dependent = FALSE;
           DriverEntry->Scheduled = TRUE;
           InsertTailList (&mScheduledQueue, &DriverEntry->ScheduledLink);
+          CoreReleaseDispatcherLock ();
+          DEBUG ((DEBUG_DISPATCH, "Evaluate DXE DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = TRUE (Apriori)\n"));
           break;
         }
       }
     }
 
-    CoreReleaseDispatcherLock ();
-
     //
     // Free data allocated by Fv->ReadSection ()
     //
diff --git a/MdeModulePkg/Core/Pei/Dependency/Dependency.c b/MdeModulePkg/Core/Pei/Dependency/Dependency.c
index 1ef14086ba..eea0feba96 100644
--- a/MdeModulePkg/Core/Pei/Dependency/Dependency.c
+++ b/MdeModulePkg/Core/Pei/Dependency/Dependency.c
@@ -5,7 +5,7 @@
   if a driver can be scheduled for execution.  The criteria for
   schedulability is that the dependency expression is satisfied.
 
-Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials                          
 are licensed and made available under the terms and conditions of the BSD License         
 which accompanies this distribution.  The full text of the license may be found at        
@@ -123,6 +123,7 @@ PeimDispatchReadiness (
         // EvalStack on the push
         //
         if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Underflow Error)\n"));
           return FALSE;
         }
 
@@ -132,11 +133,17 @@ PeimDispatchReadiness (
         //
         StackPtr->Operator = (VOID *) Iterator;
         Iterator = Iterator + sizeof (EFI_GUID);
+        DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = %a\n", StackPtr->Operator, IsPpiInstalled (PeiServices, StackPtr) ? "TRUE" : "FALSE"));
         StackPtr++;
         break;
 
       case (EFI_DEP_AND):    
       case (EFI_DEP_OR):     
+        if (*(Iterator - 1) == EFI_DEP_AND) {
+          DEBUG ((DEBUG_DISPATCH, "  AND\n"));
+        } else {
+          DEBUG ((DEBUG_DISPATCH, "  OR\n"));
+        }
         //
         // Check to make sure the dependency grammar doesn't underflow the
         // EvalStack on the two POPs for the AND operation.  Don't need to
@@ -144,6 +151,7 @@ PeimDispatchReadiness (
         // did two POPs.
         //
         if (StackPtr < &EvalStack[2]) {
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Underflow Error)\n"));
           return FALSE;
         }
 
@@ -176,18 +184,22 @@ PeimDispatchReadiness (
         break;
         
       case (EFI_DEP_END):
+        DEBUG ((DEBUG_DISPATCH, "  END\n"));
         StackPtr--;
         //
         // Check to make sure EvalStack is balanced.  If not, then there is
         // an error in the dependency grammar, so return EFI_INVALID_PARAMETER.
         //
         if (StackPtr != &EvalStack[0]) {
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Underflow Error)\n"));
           return FALSE;
         }
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = %a\n", IsPpiInstalled (PeiServices, StackPtr) ? "TRUE" : "FALSE"));
         return IsPpiInstalled (PeiServices, StackPtr);
         break;
 
       case (EFI_DEP_NOT):    
+        DEBUG ((DEBUG_DISPATCH, "  NOT\n"));
         //
         // Check to make sure the dependency grammar doesn't underflow the
         // EvalStack on the POP for the NOT operation.  Don't need to
@@ -195,6 +207,7 @@ PeimDispatchReadiness (
         // did a POP.
         //
         if (StackPtr < &EvalStack[1]) {
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Underflow Error)\n"));
           return FALSE;
         }
         (StackPtr-1)->Result = (BOOLEAN) !IsPpiInstalled (PeiServices, (StackPtr-1));
@@ -203,11 +216,17 @@ PeimDispatchReadiness (
 
       case (EFI_DEP_TRUE):
       case (EFI_DEP_FALSE):
+        if (*(Iterator - 1) == EFI_DEP_TRUE) {
+          DEBUG ((DEBUG_DISPATCH, "  TRUE\n"));
+        } else {
+          DEBUG ((DEBUG_DISPATCH, "  FALSE\n"));
+        }
         //
         // Check to make sure the dependency grammar doesn't overflow the
         // EvalStack on the push
         //
         if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Underflow Error)\n"));
           return FALSE;
         }
         //
@@ -225,6 +244,7 @@ PeimDispatchReadiness (
         break;
 
       default:
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Invalid opcode)\n"));
         //
         // The grammar should never arrive here
         //
diff --git a/MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c b/MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c
index 6198114bb1..3dd7549df8 100644
--- a/MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c
+++ b/MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c
@@ -1078,11 +1078,20 @@ DepexSatisfied (
 {
   EFI_STATUS           Status;
   VOID                 *DepexData;
+  EFI_FV_FILE_INFO     FileInfo;
 
+  Status = PeiServicesFfsGetFileInfo (FileHandle, &FileInfo);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_DISPATCH, "Evaluate PEI DEPEX for FFS(Unknown)\n"));
+  } else {
+    DEBUG ((DEBUG_DISPATCH, "Evaluate PEI DEPEX for FFS(%g)\n", &FileInfo.FileName));
+  }
+  
   if (PeimCount < Private->AprioriCount) {
     //
     // If its in the A priori file then we set Depex to TRUE
     //
+    DEBUG ((DEBUG_DISPATCH, "  RESULT = TRUE (Apriori)\n"));
     return TRUE;
   }
 
@@ -1099,6 +1108,7 @@ DepexSatisfied (
     //
     // If there is no DEPEX, assume the module can be executed
     //
+    DEBUG ((DEBUG_DISPATCH, "  RESULT = TRUE (No DEPEX)\n"));
     return TRUE;
   }
 
diff --git a/MdeModulePkg/Core/PiSmmCore/Dependency.c b/MdeModulePkg/Core/PiSmmCore/Dependency.c
index cf8c3e9ff7..4bf8502cf8 100644
--- a/MdeModulePkg/Core/PiSmmCore/Dependency.c
+++ b/MdeModulePkg/Core/PiSmmCore/Dependency.c
@@ -183,6 +183,8 @@ SmmIsSchedulable (
   EFI_GUID    DriverGuid;
   VOID        *Interface;
 
+  DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+  
   Operator = FALSE;
   Operator2 = FALSE;
 
@@ -199,6 +201,7 @@ SmmIsSchedulable (
     // A NULL Depex means that the SMM driver is not built correctly.  
     // All SMM drivers must have a valid depex expressiion.
     //
+    DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Depex is empty)\n"));
     ASSERT (FALSE);
     return FALSE;
   }
@@ -218,6 +221,7 @@ SmmIsSchedulable (
     // past the end of the dependency expression.
     //
     if (((UINTN)Iterator - (UINTN)DriverEntry->Depex) >= DriverEntry->DepexSize) {
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Attempt to fetch past end of depex)\n"));
       return FALSE;
     }
 
@@ -233,6 +237,7 @@ SmmIsSchedulable (
       // If the code flow arrives at this point, there was a BEFORE or AFTER
       // that were not the first opcodes.
       //
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected BEFORE or AFTER opcode)\n"));
       ASSERT (FALSE);
     case EFI_DEP_SOR:
       //
@@ -240,8 +245,11 @@ SmmIsSchedulable (
       // at any other location, then the dependency expression evaluates to FALSE
       //
       if (Iterator != DriverEntry->Depex) {
+        DEBUG ((DEBUG_DISPATCH, "  SOR\n"));
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected SOR opcode)\n"));
         return FALSE;
       }
+      DEBUG ((DEBUG_DISPATCH, "  SOR                                             = Requested\n"));
       //
       // Otherwise, it is the first opcode and should be treated as a NOP.
       //
@@ -263,12 +271,15 @@ SmmIsSchedulable (
       }
 
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = FALSE\n", &DriverGuid));
         Status = PushBool (FALSE);
       } else {
+        DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = TRUE\n", &DriverGuid));
         *Iterator = EFI_DEP_REPLACE_TRUE;
         Status = PushBool (TRUE);
       }
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
@@ -276,75 +287,96 @@ SmmIsSchedulable (
       break;
 
     case EFI_DEP_AND:
+      DEBUG ((DEBUG_DISPATCH, "  AND\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PopBool (&Operator2);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PushBool ((BOOLEAN)(Operator && Operator2));
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_OR:
+      DEBUG ((DEBUG_DISPATCH, "  OR\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PopBool (&Operator2);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PushBool ((BOOLEAN)(Operator || Operator2));
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_NOT:
+      DEBUG ((DEBUG_DISPATCH, "  NOT\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
       Status = PushBool ((BOOLEAN)(!Operator));
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_TRUE:
+      DEBUG ((DEBUG_DISPATCH, "  TRUE\n"));
       Status = PushBool (TRUE);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_FALSE:
+      DEBUG ((DEBUG_DISPATCH, "  FALSE\n"));
       Status = PushBool (FALSE);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
       break;
 
     case EFI_DEP_END:
+      DEBUG ((DEBUG_DISPATCH, "  END\n"));
       Status = PopBool (&Operator);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = %a\n", Operator ? "TRUE" : "FALSE"));
       return Operator;
 
     case EFI_DEP_REPLACE_TRUE:
+      CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID));
+      DEBUG ((DEBUG_DISPATCH, "  PUSH GUID(%g) = TRUE\n", &DriverGuid));
       Status = PushBool (TRUE);
       if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unexpected error)\n"));
         return FALSE;
       }
 
@@ -352,6 +384,7 @@ SmmIsSchedulable (
       break;
 
     default:
+      DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE (Unknown opcode)\n"));
       goto Done;
     }
 
diff --git a/MdeModulePkg/Core/PiSmmCore/Dispatcher.c b/MdeModulePkg/Core/PiSmmCore/Dispatcher.c
index 405f6dea48..d83224e322 100644
--- a/MdeModulePkg/Core/PiSmmCore/Dispatcher.c
+++ b/MdeModulePkg/Core/PiSmmCore/Dispatcher.c
@@ -782,9 +782,14 @@ SmmSchedule (
       DriverEntry->Unrequested  = FALSE;
       DriverEntry->Dependent    = TRUE;
 
+      DEBUG ((DEBUG_DISPATCH, "Schedule FFS(%g) - EFI_SUCCESS\n", DriverName));
+
       return EFI_SUCCESS;
     }
   }
+  
+  DEBUG ((DEBUG_DISPATCH, "Schedule FFS(%g) - EFI_NOT_FOUND\n", DriverName));
+  
   return EFI_NOT_FOUND;
 }
 
@@ -925,6 +930,12 @@ SmmDispatcher (
           SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
           ReadyToRun = TRUE;
         }
+      } else {
+        if (DriverEntry->Unrequested) {
+          DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+          DEBUG ((DEBUG_DISPATCH, "  SOR                                             = Not Requested\n"));
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = FALSE\n"));
+        }
       }
     }
   } while (ReadyToRun);
@@ -974,12 +985,17 @@ SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
   //
   for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
     DriverEntry = CR(Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
-    if (DriverEntry->Before && DriverEntry->Dependent) {
+    if (DriverEntry->Before && DriverEntry->Dependent && DriverEntry != InsertedDriverEntry) {
+      DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+      DEBUG ((DEBUG_DISPATCH, "  BEFORE FFS(%g) = ", &DriverEntry->BeforeAfterGuid));
       if (CompareGuid (&InsertedDriverEntry->FileName, &DriverEntry->BeforeAfterGuid)) {
         //
         // Recursively process BEFORE
         //
+        DEBUG ((DEBUG_DISPATCH, "TRUE\n  END\n  RESULT = TRUE\n"));
         SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
+      } else {
+        DEBUG ((DEBUG_DISPATCH, "FALSE\n  END\n  RESULT = FALSE\n"));
       }
     }
   }
@@ -998,12 +1014,17 @@ SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
   //
   for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
     DriverEntry = CR(Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
-    if (DriverEntry->After && DriverEntry->Dependent) {
+    if (DriverEntry->After && DriverEntry->Dependent && DriverEntry != InsertedDriverEntry) {
+      DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+      DEBUG ((DEBUG_DISPATCH, "  AFTER FFS(%g) = ", &DriverEntry->BeforeAfterGuid));
       if (CompareGuid (&InsertedDriverEntry->FileName, &DriverEntry->BeforeAfterGuid)) {
         //
         // Recursively process AFTER
         //
+        DEBUG ((DEBUG_DISPATCH, "TRUE\n  END\n  RESULT = TRUE\n"));
         SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
+      } else {
+        DEBUG ((DEBUG_DISPATCH, "FALSE\n  END\n  RESULT = FALSE\n"));
       }
     }
   }
@@ -1340,6 +1361,8 @@ SmmDriverDispatchHandler (
           DriverEntry->Dependent = FALSE;
           DriverEntry->Scheduled = TRUE;
           InsertTailList (&mScheduledQueue, &DriverEntry->ScheduledLink);
+          DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
+          DEBUG ((DEBUG_DISPATCH, "  RESULT = TRUE (Apriori)\n"));
           break;
         }
       }
-- 
2.39.2