DisplayPort Link Power Management for Intermediate Devices

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Solution Overview

Problem

Existing link power management techniques, such as those in the VESA Embedded DisplayPort (eDP) Standard, do not effectively manage power over an entire display topology that includes intermediate devices, leading to inefficiencies in power usage, especially with advanced display panel technologies like Adaptive Refresh and Adaptive Sync panels.

Innovation Solution

The implementation of advanced link power management (ALPM) techniques that allow the Main-Link to be turned off during the vertical blanking period, using low latency entry and exit mechanisms into and from low power states, and defining multiple power management states with varying exit latency requirements to optimize resource power-down in the display topology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the Main-Link is kept active continuously, then the display topology can respond immediately to frame transmission, but power consumption increases significantly

Engineering Contradiction:

Improvepower consumptionVSAvoidresponse time

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent implements dynamic power management by allowing the Main-Link to transition between active and low-power states based on real-time transmission needs. The link adapts its operational state rather than remaining static, entering low-power mode during vertical blanking periods and active states during frame transmission, thereby optimizing the trade-off between power consumption and response time

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs periodic activation of the Main-Link synchronized with the display refresh rate. The link is activated periodically during vertical blanking periods to transmit control characters and data, then enters low-power states between these periodic intervals, reducing overall power consumption while maintaining necessary communication functionality

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the Main-Link is turned off during vertical blanking period, then power savings are achieved, but link reactivation latency increases

Engineering Contradiction:

Improvepower consumptionVSAvoidreactivation latency

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by maintaining certain link states and buffers during the active period that facilitate rapid reactivation. Control characters and transmission data are prepared in advance and queued, so when the link needs to reactivate, the transition is faster because the necessary signaling and data are already positioned for immediate transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If multiple power management states are defined with varying exit latency, then resource power-down is optimized, but system complexity increases

Engineering Contradiction:

Improvepower efficiencyVSAvoidpower management complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent segments the power management system into distinct operational states (active, low-power, and different levels of power-down) with clearly defined transition criteria. Each state has specific characteristics regarding power consumption and exit latency, allowing the system to select the appropriate state based on current needs. This segmentation organizes the complexity into manageable, well-defined segments rather than a continuous spectrum of states

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12271249B2Advanced link power management for displayport

Publication Date: 2025.04.08 INTEL CORP

AI summary

An apparatus comprising circuitry to buffer video data; and a DisplayPort Transmitter to communicate the video data to a DisplayPort Receiver via a virtual channel through at least one intermediate device between the DisplayPort Transmitter and the DisplayPort Receiver, wherein the virtual channel comprises a unidirectional Main-Link and a bidirectional auxiliary channel (AUX_CH); and communicate a power down signal over the Main-Link to the at least one intermediate device and the DisplayPort Receiver in conjunction with turning off the Main-Link to place the at least one intermediate device and the DisplayPort Receiver in respective low power states.