From fa08f7e7bf4d43442e5be63645a95d5b675181dd Mon Sep 17 00:00:00 2001
From: John Davis <goldfishnet64@outlook.com>
Date: Mon, 28 Aug 2023 18:23:55 -0500
Subject: [PATCH] OcCpuLib: Fallback to DUET on AMD with invalid PM timer
 address

---
 Library/OcCpuLib/FrequencyDetect.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Library/OcCpuLib/FrequencyDetect.c b/Library/OcCpuLib/FrequencyDetect.c
index 63c8367b..63b6cc7f 100644
--- a/Library/OcCpuLib/FrequencyDetect.c
+++ b/Library/OcCpuLib/FrequencyDetect.c
@@ -136,8 +136,12 @@ InternalGetPmTimerAddr (
       TimerAddr = MmioRead32 (
                     R_AMD_ACPI_MMIO_BASE + R_AMD_ACPI_MMIO_PMIO_BASE + R_AMD_ACPI_PM_TMR_BLOCK
                     );
-      if (Type != NULL) {
-        *Type = "AMD";
+      if (TimerAddr == UINT32_MAX) {
+        TimerAddr = 0;
+      } else {
+        if (Type != NULL) {
+          *Type = "AMD";
+        }
       }
     }
   }