Packet Link Width Negotiation Using Control-Line Signals
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Solution Overview
Problem
Existing communication link architectures, such as PCI Express, require complex methods for negotiating link widths, which can limit performance and flexibility in configuring link topologies.
Innovation Solution
A technique that allows devices to negotiate link width by detecting signals on control lines during initialization, enabling configuration of links as single or multiple sublinks, facilitating different topologies by ganging or unganging sublinks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PCIe architecture uses complex method for link width negotiation with serial information exchange, then link width can be negotiated, but device complexity and initialization time increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring link width indication bits in the device status register before initialization occurs. During initialization, the remote device can directly read these pre-configured bits to determine the desired link width, eliminating the need for complex serial negotiation protocols. This resolves the contradiction by maintaining adaptability while reducing device complexity and initialization overhead.
Solution Approach 2:
The patent extracts the link width negotiation information from the complex serial negotiation process and places it into dedicated indication bits within the device status register. This separation allows the link width to be determined through simple bit reading rather than complex protocol exchange, reducing negotiation method complexity while preserving the ability to negotiate different link widths.
2Adaptability or versatility
If PCIe architecture requires every lane to exchange identifying information serially, then link topology can be established, but initialization time increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring link width indication bits in the device status register before initialization occurs. During initialization, the remote device can directly read these pre-configured bits to determine the desired link width, eliminating the need for complex serial negotiation protocols. This resolves the contradiction by maintaining adaptability while reducing device complexity and initialization overhead.
3Productivity
If link width is fixed at maximum width, then bandwidth is maximized, but flexibility in configuring different topologies is reduced
Solution Approach 1:
The patent applies dynamics by making the link width configurable through indication bits that can be set to different values. The system can dynamically adjust the link width based on the specific topology and performance requirements, rather than being fixed at maximum width. This resolves the contradiction by allowing the link to operate at maximum bandwidth when needed while providing flexibility to reduce width for different topology configurations.
Solution Approach 2:
The patent applies parameter changes by using indication bits to control the link width parameter. By changing the value of these bits, the system can adjust the operational link width to match different topology requirements and performance levels, enabling both maximum bandwidth operation and flexible topology configuration.
Data Source
AI summary
A technique for negotiating the width of a link between a first device and a second device includes detecting, during initialization, a respective signal on one or more control lines associated with at least a portion of an N-bit link. The N-bit link is configured as a single link having a width of N or multiple sublinks having a width less than N based on a respective value of the respective signal on the one or more control lines.