PCI Device Power Management via State Preservation

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Solution Overview

Problem

Current data processing systems face inefficiencies in power management, particularly with PCI devices that remain unused for extended periods, leading to unnecessary power consumption and potential system instability during reactivation.

Innovation Solution

Implement a method to selectively power down unused PCI devices after a predetermined period, using a timer and resource analysis to determine device usage, and restore power quickly with reduced initialization when needed, leveraging existing OS tools like HP-UX's olrad command to manage device states and drivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power is continuously supplied to PCI devices, then device availability is improved, but power consumption increases

Engineering Contradiction:

Improvedevice availabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the power state of PCI devices based on their usage status. Devices are monitored for inactivity periods, and power is selectively suspended after a predetermined time threshold is exceeded, while maintaining quick reactivation capability through preserved configuration data and driver state information.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If power is suspended to PCI slots, then power consumption is reduced, but device reactivation time increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddevice reactivation time

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

Before suspending power to a PCI device, the system performs preliminary actions by saving the device configuration data and driver state information to persistent storage. This preliminary preservation of state information enables rapid reactivation without requiring full initialization sequences, thus reducing reactivation time while maintaining power savings.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If full initialization is performed upon device reactivation, then device reliability is improved, but reactivation time increases

Engineering Contradiction:

Improvedevice reliabilityVSAvoidreactivation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs a partial initialization process upon device reactivation rather than a complete initialization. By utilizing previously saved configuration data and driver state information, the system restores devices with minimal processing, achieving sufficient reliability for most operations without the time cost of full initialization sequences.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8046608B2Method and system for managing power supply to at least one device

Publication Date: 2011.10.25 HEWLETT PACKARD ENTERPRISE DEV LP

AI summary

A method of managing power supply to at least one device in a data processing system, the method comprising determining when the at least one device has been associated with no resources for a predetermined period of time; turning off the power supply to the at least one device; determining that the at least one device is required for use by the data processing system; and restoring the power supply to the at least one device.