Optical DisplayPort Link Training for Stable Multi-Display Output
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Solution Overview
Problem
Optical links experience data transfer errors and instability due to transmission delays or distortions during link training and changes in connection states, leading to screen dislocation and video output delays in display systems.
Innovation Solution
An optical link with a main link for video information and an auxiliary channel for setting data, utilizing control signals to switch connections and adjust setting information dynamically, optimizing link settings to prevent errors and instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the auxiliary channel uses a single transmission line for bidirectional communication, then device complexity is reduced, but data transfer errors occur due to transmission delays and distortion during link training
Solution Approach 1:
The auxiliary channel is segmented into two separate transmission lines: one dedicated for transmitting requests from display source to display sink, and another for transmitting responses from display sink to display source. This segmentation eliminates signal collision and transmission delays that occur in bidirectional single-line communication, thereby ensuring reliable data transfer during link training while maintaining relatively simple device structure.
2Adaptability or versatility
If link training is performed with display sink requests, then the link settings are configured, but data transfer errors occur due to non-linearity between input and output in the optical link
Solution Approach 1:
The optical link performs preliminary actions by transmitting control signals to switch connections before actual data transfer. Specifically, the system switches the display sink connection to the first transmission line before the display source transmits requests, and switches the display source connection to the second transmission line before the display sink transmits responses. This preliminary connection switching ensures that communication paths are established in advance, preventing data transfer errors caused by non-linearity and ensuring reliable link training.
Solution Approach 2:
The optical link introduces intermediary control signals that mediate the connection switching between display source and display sink. These control signals coordinate the timing of connection establishment, ensuring that both ends are properly connected before data transmission begins, thereby eliminating errors caused by premature or mismatched connection states.
3Adaptability or versatility
If the display sink connection state changes, then the system adapts to new configurations, but screen dislocation and video output delays occur due to re-setting of the main link
Solution Approach 1:
The auxiliary channel maintains continuous communication capability during connection state changes by using separate transmission lines for requests and responses. This continuity allows the system to quickly detect and respond to connection changes without interrupting the main link, thereby preventing screen dislocation and video output delays that would occur with complete re-setting.
Data Source
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AI summary
The present disclosure provides an optical link. According to the present disclosure, the optical link supports duplex communication of an auxiliary channel for transmitting, between a display source and a display sink, extended display configuration data (EDID) that is related to rendering of the display sink or display port configuration data (DPCD) related to setting of a main link. The optical link according to the present disclosure is capable of preventing a data transfer error despite a transmission delay or distortion due to non-linearity between an input and an output due to movement of the optical link by setting the main link to be optimized for the optical link, which is different from a request by the display sink with respect to setting of a training pattern, in link training between the display source and the display sink. According to the optical link according to the present disclosure, in one-to-multi display in which a plurality of display sinks are connected to one display source, dislocation or instability of the arrangement of a plurality of screens, which may be caused by a change in a connection state of any one display sink, may be prevented, and after the display sink returns to a normal connection state, delay of a video output for the resetting of the main link may be prevented.