Re: [PATCH] UefiCpuPkg/FeaturesLib: Fix Haswell CPU hang with 50% throttling

["Dong, Eric" <eric.dong@intel.com>]

Reviewed-by: Eric Dong <eric.dong@intel.com>

-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Ruiyu Ni
Sent: Tuesday, February 6, 2018 3:27 PM
To: edk2-devel@lists.01.org
Cc: Dong, Eric <eric.dong@intel.com>
Subject: [edk2] [PATCH] UefiCpuPkg/FeaturesLib: Fix Haswell CPU hang with 50% throttling

Today's implementation only assumes SandyBridge CPU supports Extended On-Demand Clock Modulation Duty Cycle.
Actually it is supported when CPUID.06h.EAX[5] == 1.

When platform requests 50% throttling, it causes value 1000b set to the low-4 bits of IA32_CLOCK_MODULATION.
But the wrong code sets 1000b to bits[1-3] which causes assertion.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jeff Fan <vanjeff_919@hotmail.com>
Cc: Eric Dong <eric.dong@intel.com>
---
 .../Library/CpuCommonFeaturesLib/ClockModulation.c | 52 ++++++++++------------
 1 file changed, 23 insertions(+), 29 deletions(-)

diff --git a/UefiCpuPkg/Library/CpuCommonFeaturesLib/ClockModulation.c b/UefiCpuPkg/Library/CpuCommonFeaturesLib/ClockModulation.c
index 56e53561e9..84d59de78f 100644
--- a/UefiCpuPkg/Library/CpuCommonFeaturesLib/ClockModulation.c
+++ b/UefiCpuPkg/Library/CpuCommonFeaturesLib/ClockModulation.c
@@ -1,7 +1,7 @@
 /** @file
   Clock Modulation feature.
 
-  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2017 - 2018, 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 @@ -67,40 +67,34 @@ ClockModulationInitialize (
   IN BOOLEAN                           State
   )
 {
-  if (IS_SANDY_BRIDGE_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel)) {
-    CPU_REGISTER_TABLE_WRITE_FIELD (
-      ProcessorNumber,
-      Msr,
-      MSR_SANDY_BRIDGE_IA32_CLOCK_MODULATION,
-      MSR_SANDY_BRIDGE_IA32_CLOCK_MODULATION_REGISTER,
-      Bits.OnDemandClockModulationDutyCycle,
-      PcdGet8 (PcdCpuClockModulationDutyCycle)
-      );
-    CPU_REGISTER_TABLE_WRITE_FIELD (
-      ProcessorNumber,
-      Msr,
-      MSR_SANDY_BRIDGE_IA32_CLOCK_MODULATION,
-      MSR_SANDY_BRIDGE_IA32_CLOCK_MODULATION_REGISTER,
-      Bits.OnDemandClockModulationEnable,
-      (State) ? 1 : 0
-      );
-  } else {
-    CPU_REGISTER_TABLE_WRITE_FIELD (
-      ProcessorNumber,
-      Msr,
-      MSR_IA32_CLOCK_MODULATION,
-      MSR_IA32_CLOCK_MODULATION_REGISTER,
-      Bits.OnDemandClockModulationDutyCycle,
-      PcdGet8 (PcdCpuClockModulationDutyCycle)
-      );
+  CPUID_THERMAL_POWER_MANAGEMENT_EAX   ThermalPowerManagementEax;
+  AsmCpuid (CPUID_THERMAL_POWER_MANAGEMENT, 
+ &ThermalPowerManagementEax.Uint32, NULL, NULL, NULL);
+
+  CPU_REGISTER_TABLE_WRITE_FIELD (
+    ProcessorNumber,
+    Msr,
+    MSR_IA32_CLOCK_MODULATION,
+    MSR_IA32_CLOCK_MODULATION_REGISTER,
+    Bits.OnDemandClockModulationDutyCycle,
+    PcdGet8 (PcdCpuClockModulationDutyCycle) >> 1
+    );
+  if (ThermalPowerManagementEax.Bits.ECMD == 1) {
     CPU_REGISTER_TABLE_WRITE_FIELD (
       ProcessorNumber,
       Msr,
       MSR_IA32_CLOCK_MODULATION,
       MSR_IA32_CLOCK_MODULATION_REGISTER,
-      Bits.OnDemandClockModulationEnable,
-      (State) ? 1 : 0
+      Bits.ExtendedOnDemandClockModulationDutyCycle,
+      PcdGet8 (PcdCpuClockModulationDutyCycle) & BIT0
       );
   }
+  CPU_REGISTER_TABLE_WRITE_FIELD (
+    ProcessorNumber,
+    Msr,
+    MSR_IA32_CLOCK_MODULATION,
+    MSR_IA32_CLOCK_MODULATION_REGISTER,
+    Bits.OnDemandClockModulationEnable,
+    (State) ? 1 : 0
+    );
   return RETURN_SUCCESS;
 }
--
2.16.1.windows.1

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