BMC Reset via Hardware Watchdog and CPLD
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Solution Overview
Problem
In server architecture, a malfunctioning or hung baseboard management controller (BMC) severely impacts the performance and capability of server systems, as existing technologies lack effective mechanisms for timely and reliable reset or recovery.
Innovation Solution
The implementation of a hardware watch-dog-timer (HW WDT) circuit and complex programmable logic device (CPLD) to monitor heartbeat signals and health conditions of the BMC, with the CPLD generating reset signals to address component failures, and a physical layer IC for remote management and communication, enabling remote reset capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a BMC is used to monitor and control server system management functions, then system management capability is improved, but the risk of system failure increases when the BMC malfunctions or hangs
Solution Approach 1:
The patent introduces a CPLD (Complex Programmable Logic Device) as an intermediary component between the BMC and the system components. The CPLD independently monitors the BMC's health status through heartbeat signals and can directly reset the BMC or other system components without requiring BMC intervention. This mediator architecture ensures that even when the BMC fails, the CPLD can maintain system control and perform recovery operations, thus resolving the reliability issue while preserving management capabilities.
2Ease of operation
If existing BMC reset mechanisms are used, then reset functionality is provided, but the reset process is delayed and unreliable when BMC hangs
Solution Approach 1:
The patent implements a hardware watchdog timer (HW WDT) circuit that continuously monitors BMC heartbeat signals in advance. When the BMC fails to send heartbeat signals within a predetermined time threshold, the HW WDT automatically triggers a reset signal through the CPLD. This preliminary monitoring and automatic trigger mechanism eliminates the need for manual intervention and reduces reset delay time, ensuring timely recovery when the BMC hangs.
3Measurement precision
If BMC health monitoring is implemented, then system health awareness is improved, but the complexity of the monitoring system increases
Solution Approach 1:
The patent implements a self-service monitoring architecture where the CPLD autonomously monitors BMC health status by receiving and evaluating heartbeat signals from the BMC. The CPLD contains internal logic that automatically compares heartbeat intervals against predetermined thresholds and triggers appropriate actions without external intervention. This self-service approach provides precise health monitoring while minimizing system complexity by consolidating monitoring and control functions within the CPLD itself, eliminating the need for separate complex monitoring systems.
Data Source
AI summary
The present disclosure provides a system and method for resetting a hang-up baseboard management controller (BMC), or another component of a server system using a hardware watch-dog-timer (HW WDT) circuit and/or complex programmable logic device (CPLD). The HW WDT circuit can monitor heartbeat signals from the BMC, and determine the health condition of the BMC. In an event that the BMC's health condition fails to meet a predefined criterion, the HW WDT circuit generates a reset signal to reset the BMC. The CPLD can collect from the BMC, health information of components of the server system. The CPLD can also collect the BMC's health condition from the HW WDT circuit. Upon determining which specific component of the server system hangs up, the CPLD can generate a reset signal to reset the specific component.