USB Type-C Subsystem Power Management for Fixed Display Ports
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Solution Overview
Problem
Processor systems with integrated USB Type-C ports, configured with fixed Display Port (DP) or High-Definition Multimedia Interface (HDMI) ports, fail to achieve the lowest power state even when no display device is attached, leading to unnecessary power consumption.
Innovation Solution
A hardware-based wake detection and system-on-chip (SoC) firmware support for servicing DP and HDMI port hot plug events, allowing the USB Type-C subsystem to enter a powered-off state (D3COLD) when no display is streaming, and autonomously re-enter this state when necessary, using a power management agent with rising edge detection logic and microcontroller to manage power states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fixed Display Port or HDMI port configuration is used in USB Type-C subsystem, then display connectivity is ensured, but the subsystem cannot achieve lowest power state when no display device is attached
Solution Approach 1:
The patent implements dynamic power state management where the USB Type-C subsystem transitions between active and low-power states based on real-time detection of display device connections and streaming activity. The system dynamically adjusts its power state rather than remaining in a fixed configuration, allowing it to achieve lowest power state when no display is attached while maintaining display connectivity when needed.
Solution Approach 2:
The patent employs feedback mechanisms through hot plug detect events and streaming status monitoring to control power state transitions. The system continuously monitors whether a display device is connected and whether streaming is active, using this feedback information to determine when to enter or exit low-power state, thereby optimizing power consumption while maintaining functionality.
2Loss of energy
If USB Type-C subsystem enters low power state frequently, then power savings are achieved, but wake-up events must be handled efficiently to maintain display functionality
Solution Approach 1:
The patent implements preliminary action by setting up wake-up event handlers and detection logic before the system enters low-power state. The power management agent is pre-configured with the ability to detect connection events and streaming status changes, ensuring that when wake-up is needed, the system can quickly and efficiently transition back to active state without complex real-time decision-making during the low-power state.
Data Source
AI summary
Hardware-based wake detection and system-on-chip (SoC) firmware support for servicing fixed display port (DP) and High Definition Multimedia Interface (HDMI) port hot plug events which allow a Universal Serial Bus (USB) Type-C subsystem to go into a powered off state while the fixed display is not streaming. Upon receiving a display software-initiated wake for fixed display streaming in response to a hot plug detect, the SoC USB Type-C firmware triggers exit low-power state flow to power up the USB USB Type-C subsystem to handle the display traffic. The SoC USB Type-C firmware has the capability to autonomously re-enter the low power state when the fixed display(s) are not streaming.