1 files changed, 16 insertions, 13 deletions
diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
index 0fbfa4bcee..9242a2e826 100644
--- a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
+++ b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
@@ -270,13 +270,6 @@ PcRtcInit (
   Time.Year   = RtcRead (RTC_ADDRESS_YEAR);
 
   //
-  // Set RTC configuration after get original time
-  // The value of bit AIE should be reserved.
-  //
-  RegisterB.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterB) | (RegisterB.Data & BIT5);
-  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
-
-  //
   // Release RTC Lock.
   //
   if (!EfiAtRuntime ()) {
@@ -331,6 +324,13 @@ PcRtcInit (
   }
 
   //
+  // Set RTC configuration after get original time
+  // The value of bit AIE should be reserved.
+  //
+  RegisterB.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterB) | (RegisterB.Data & BIT5);
+  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
+
+  //
   // Reset time value according to new RTC configuration
   //
   Status = PcRtcSetTime (&Time, Global);
@@ -995,13 +995,16 @@ ConvertRtcTimeToEfiTime (
   BOOLEAN  IsPM;
   UINT8    Century;
 
-  if ((Time->Hour & 0x80) != 0) {
-    IsPM = TRUE;
-  } else {
-    IsPM = FALSE;
-  }
+  // IsPM only makes sense for 12-hour format.
+  if (RegisterB.Bits.Mil == 0) {
+    if ((Time->Hour & 0x80) != 0) {
+      IsPM = TRUE;
+    } else {
+      IsPM = FALSE;
+    }
 
-  Time->Hour = (UINT8)(Time->Hour & 0x7f);
+    Time->Hour = (UINT8)(Time->Hour & 0x7f);
+  }
 
   if (RegisterB.Bits.Dm == 0) {
     Time->Year   = CheckAndConvertBcd8ToDecimal8 ((UINT8)Time->Year);