Central Processing Unit (CPU) Voltage Regulator Device (VRD) fault with C-State enabled - IBM System x

Resolving The Problem

Source

RETAIN tip: H21413

Symptom

An IBM System x3100 M4 or x3250 M4 may power off unexpectedly with the Central Processing Unit (CPU) C-state enabled during the operation. The system is able to power on again by AC cycle.

The following conditions are observed:

Panel Lightpath:

• Fault Light Emitting Diode (LED) will illuminated.

Integrated Management Module (IMM) event:

• Sensor 'system board Fault' has transitioned to critical from a less state.

Affected configurations

The system may be any of the following IBM servers:

• System x3100 M4, type 2582, any model
• System x3250 M4, type 2583, any model

This tip is not software specific.

This tip is not option specific.

Solution

Set the Advanced Configuration and Power Interface (ACPI) CPU C-State as disabled by using the following method:

1. Enter Unified Extensible Firmware Interface (UEFI) Setup by pressing F1 after the IBM System x Server Firmware logo screen appears when the system is powered on or restarted.
   
2. Select System Settings --> Processors
   
3. Set CPU C-States to Disable
   
4. Press Escape (Esc), press 'Y' to save the settings and restart the server.
   

Additional information

In rare cases, processor Voltage Regulator Device (VRD) faults have been observed when a processor transitions between C-state 0 (full power) and deep C-states.

When system CPU C-state is enabled, the negative current occurred during the CPU C-state transitions that resulted in the VRD turning itself off.