(MdeModulePkg\Core\Dxe\Event\Tpl.c) line 120-122
-----------------------------------------------------------------
120  if (OldTpl >= TPL_HIGH_LEVEL  &&  NewTpl < TPL_HIGH_LEVEL) {
121    gEfiCurrentTpl = TPL_HIGH_LEVEL;
122  }
-----------------------------------------------------------------

First, the newly assigned *gEfiCurrentTpl* is never used before next
re-assignment by the code that follows.

Second, The "OldTpl" comes from "gEfiCurrentTpl".
If "OldTpl >= TPL_HIGH_LEVEL" holds, the timer interrupt *must* have
been disabled according to the semantic of TPL_HIGH_LEVEL.
Since Uefi FW executes as single-threaded *strictly*, no other code
will possibly visit the "gEfiCurrentTpl".

So the 3 lines of code should be redundant.

Contributed-under: TianoCore Contribution Agreement 1.1
Suggested-by: Ming Shao <ming.shao@intel.com>
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
---
 MdeModulePkg/Core/Dxe/Event/Tpl.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/MdeModulePkg/Core/Dxe/Event/Tpl.c b/MdeModulePkg/Core/Dxe/Event/Tpl.c
index e3caf832b8..5f60fd077f 100644
--- a/MdeModulePkg/Core/Dxe/Event/Tpl.c
+++ b/MdeModulePkg/Core/Dxe/Event/Tpl.c
@@ -113,15 +113,6 @@ CoreRestoreTpl (
   ASSERT (VALID_TPL (NewTpl));
 
   //
-  // If lowering below HIGH_LEVEL, make sure
-  // interrupts are enabled
-  //
-
-  if (OldTpl >= TPL_HIGH_LEVEL  &&  NewTpl < TPL_HIGH_LEVEL) {
-    gEfiCurrentTpl = TPL_HIGH_LEVEL;
-  }
-
-  //
   // Dispatch any pending events
   //
   while (gEventPending != 0) {
@@ -131,6 +122,10 @@ CoreRestoreTpl (
     }
 
     gEfiCurrentTpl = PendingTpl;
+    //
+    // If lowering below HIGH_LEVEL, make sure
+    // interrupts are enabled
+    //
     if (gEfiCurrentTpl < TPL_HIGH_LEVEL) {
       CoreSetInterruptState (TRUE);
     }
-- 
2.12.2.windows.2

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