Dynamic PCIe Lane Direction Switching for Asymmetric Bandwidth

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Solution Overview

Problem

PCIe systems face challenges in managing bandwidth efficiently due to asymmetrical bandwidth allocation, leading to underutilization or oversubscription of lanes, which affects user experience and system performance, especially in applications like display where downstream bandwidth exceeds upstream bandwidth.

Innovation Solution

Implementing dynamic high-speed lane direction switching, allowing the system manager to configure lanes asymmetrically based on device requirements, using retimers to extend link reach and manage lane direction dynamically without disrupting current traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If lanes are allocated symmetrically in PCIe systems, then system simplicity and ease of configuration are maintained, but bandwidth utilization efficiency deteriorates due to underutilization or oversubscription of lanes

Engineering Contradiction:

Improvebandwidth utilization efficiencyVSAvoidlane configuration complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic lane direction switching that allows lanes to change their transmission direction based on real-time bandwidth requirements. The system manager can dynamically reconfigure lanes from symmetric to asymmetric configuration, enabling the interconnect to adapt to varying bandwidth demands without physical hardware changes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of PCIe lanes by switching their transmission direction (upstream/downstream) based on bandwidth requirements. This parameter change allows the same physical lanes to serve different functional roles, optimizing bandwidth utilization for asymmetric workloads such as display applications

Inventive Principle:

Principle #35Parameter changes

2Productivity

If lane direction is switched dynamically to optimize bandwidth, then bandwidth utilization improves, but system complexity and potential disruption to existing traffic flows worsen

Engineering Contradiction:

Improvebandwidth utilizationVSAvoidtraffic flow stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs lane direction switching during link initialization or reconfiguration phases before normal data traffic begins. By completing the lane direction configuration in advance, the system ensures that when data transmission starts, all lanes are already properly configured, preventing any disruption to traffic flows

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system manager acts as an intermediary that coordinates lane direction switching between connected devices. It manages the reconfiguration process by coordinating with both ends of the link, ensuring that lane direction changes are synchronized and do not cause traffic disruptions

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11474967B2Systems, methods, and devices for dynamic high speed lane direction switching for asymmetrical interfaces

Publication Date: 2022.10.18 INTEL CORP

AI summary

Systems, devices, computer program products, and methods include determining by a connection manager that a connected device can be enhanced by an asymmetrical multi-lane link. The connection manager can use system parameters, including bandwidth information, to switch a direction of one or more lanes of the multi-lane link. The connection manager can use register setting instructions to change register settings on the host side and on the device side to switch the direction of one or more lanes of the multi-lane link.