From 06fe0d63a28fb6cb84a234ebaaf260aad80a46dd Mon Sep 17 00:00:00 2001
From: Mike Beaton <mjsbeaton@gmail.com>
Date: Tue, 25 Oct 2022 04:54:04 +0100
Subject: [PATCH] OcCpuLib: Cache InternalCalculateARTFrequencyIntel failure to
 avoid log loop

---
 Changelog.md                       |  1 +
 Library/OcCpuLib/FrequencyDetect.c | 15 ++++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index 3be4c229..fd29a32d 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -6,6 +6,7 @@ OpenCore Changelog
 - Fixed maximum click duration and double click speed for non-standard poll frequencies
 - Added support for pointer dwell-clicking
 - Prevented Apple firmware from adding additional security checks on top of emulated NVRAM driver
+- Fixed recursive loop on first log protocol line on some systems
 
 #### v0.8.5
 - Updated builtin firmware versions for SMBIOS and the rest
diff --git a/Library/OcCpuLib/FrequencyDetect.c b/Library/OcCpuLib/FrequencyDetect.c
index 2c4da147..49513b20 100644
--- a/Library/OcCpuLib/FrequencyDetect.c
+++ b/Library/OcCpuLib/FrequencyDetect.c
@@ -447,8 +447,9 @@ InternalCalculateARTFrequencyIntel (
   // this frequency on module entry to initialise a TimerLib instance, and at
   // a later point in time to gather CPU information.
   //
-  STATIC UINT64  ARTFrequency        = 0;
-  STATIC UINT64  CPUFrequencyFromART = 0;
+  STATIC BOOLEAN  ObtainedARTFreq     = FALSE;
+  STATIC UINT64   ARTFrequency        = 0;
+  STATIC UINT64   CPUFrequencyFromART = 0;
 
   UINT32  MaxId;
   UINT32  CpuVendor;
@@ -463,11 +464,14 @@ InternalCalculateARTFrequencyIntel (
   UINT8                          Model;
 
   if (Recalculate) {
+    ObtainedARTFreq     = FALSE;
     ARTFrequency        = 0;
     CPUFrequencyFromART = 0;
   }
 
-  if (ARTFrequency == 0) {
+  if (!ObtainedARTFreq) {
+    ObtainedARTFreq = TRUE;
+
     //
     // Get vendor CPUID 0x00000000
     //
@@ -686,6 +690,11 @@ InternalCalculateVMTFrequency (
   return CpuidEax * 1000ULL;
 }
 
+//
+// This function and everything called by it must not log (after the first early call
+// to it, which can log and cache results), otherwise it will generate a loop when it
+// gets called during first log line.
+//
 UINT64
 OcGetTSCFrequency (
   VOID