Host Controller Idle Detection for Peripheral Power Reduction

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Solution Overview

Problem

Existing power management techniques in computer systems fail to accurately identify idle states in bus-attached peripheral devices, leading to inefficient power consumption and increased heat generation, particularly in mobile devices.

Innovation Solution

A host controller infers idleness based on activity vectors generated by peripheral devices, distinguishing between data transfer and handshaking or control activities, and communicates an idleness indicator to a power manager to transition components into low-power states while maintaining communication capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If components remain in normal operating mode to maintain communication capabilities, then communication reliability is improved, but power consumption increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the power state of components based on real-time activity detection. The host controller monitors bus activity and selectively transitions components between active and low-power states, allowing the system to adapt its power consumption level according to actual communication needs rather than remaining in a fixed state

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The host controller continuously monitors bus activity and uses this feedback to determine when components can safely enter low-power states. The activity vector generated by the host controller provides feedback about peripheral device status, enabling intelligent power management decisions that balance communication reliability with power savings

Inventive Principle:

Principle #23Feedback

2Use of energy by moving object

If components enter low-power states to reduce power consumption, then power consumption is reduced, but communication capability deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidcommunication capability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The host controller performs preliminary actions by maintaining monitoring capabilities and activity vector generation even when components are in low-power states. This preliminary preparation ensures that when communication is needed, the system can quickly transition components back to active state without losing communication capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The host controller acts as an intermediary between power management and communication functions. It mediates by maintaining a simplified representation of peripheral device activity (the activity vector) that allows power management decisions to be made without completely isolating communication capabilities

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If existing power management techniques are used, then implementation simplicity is maintained, but idle state detection accuracy deteriorates

Engineering Contradiction:

Improveimplementation simplicityVSAvoididle state detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The host controller performs self-service by generating its own activity vector based on monitored bus activity. This self-generated activity vector provides accurate idle state detection without requiring external intervention or complex additional hardware, maintaining implementation simplicity while improving detection accuracy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the parameter used for idle state detection from simple activity presence/absence to a more nuanced activity vector that captures the nature of bus activity. This parameter change enables accurate distinction between idle and active states while maintaining relatively simple implementation through the host controller's existing monitoring capabilities

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12554663B2Host controller and bus-attached peripheral device power consumption reduction

Publication Date: 2026.02.17 ADVANCED MICRO DEVICES INC

AI summary

Systems, apparatuses, and methods for a host controller inferring idleness based on activity generated by a bus-attached peripheral device are disclosed. A host controller detects activity by a first device attached to the host controller via a first bus. The host controller generates an activity vector based on the detected activity, and the host controller determines whether the activity vector indicates that the first device is only engaging in handshaking or control activity rather than data transfer. If the first device is merely communicating status information, then the host controller infers idleness and conveys an idleness indicator to a power manager. The power manager turns off power to system memory and/or other components based on the idleness indicator, but keeps enough power on to allow the host controller to communicate with the first device for handshaking or status purposes.