USB Function Buffer Data Loss Prevention During Setting Changeover
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Solution Overview
Problem
When the setting of End Points serving as transmission/reception buffers in a USB Function is changed, existing technologies risk losing data stored in these buffers, particularly in high-speed USB environments like USB 3.0, where data overflow can occur due to filled buffers.
Innovation Solution
Implementing a method where the USB Function responds with a retransmission request (NACK) when the data transfer to the internal memory is not complete, allowing for delayed Alternate setting changeover and ensuring data is not lost during buffer initialization, using ACK and NACK responses according to USB standards, and potentially utilizing NRDY for Super Speed USB 3.0.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the End Point setting is changed to improve data transmission efficiency in USB 3.0, then data transmission speed is improved, but data stored in the End Point buffer is lost
Solution Approach 1:
The patent checks whether data transfer to internal memory is complete before allowing Alternate setting changeover. This preliminary verification ensures that all data in the End Point buffer is transferred to internal memory before the buffer is initialized, preventing data loss while enabling speed improvements through setting changes.
Solution Approach 2:
The patent implements a feedback mechanism where the USB Function monitors the completion status of data transfer to internal memory and uses this information to control whether Alternate setting changeover is permitted. This feedback loop ensures data integrity while maintaining efficient data transmission.
2Quantity of substance
If the End Point buffer size is increased to handle high-speed USB 3.0 data flow, then data reception capability is improved, but data overflow occurs when buffers are filled
Solution Approach 1:
The patent monitors the fill status of End Point buffers and provides feedback control on Alternate setting changeover. When buffers are filled, the system prevents setting changes that would cause data loss, while allowing changes when buffers are empty, thus preventing overflow while maximizing data reception capability.
Solution Approach 2:
The patent dynamically controls the permission for Alternate setting changeover based on real-time buffer status. The system adapts its behavior according to whether data transfer is complete, enabling flexible buffer management that prevents overflow while maintaining high data reception capability.
3Productivity
If Alternate setting changeover is performed frequently to optimize transmission modes, then transmission efficiency is improved, but data loss occurs due to buffer initialization
Solution Approach 1:
The patent performs a preliminary check of data transfer completion status before permitting Alternate setting changeover. This ensures that data is safely transferred to internal memory before the End Point buffer is reinitialized, preventing data loss while allowing frequent setting changes for optimization.
Solution Approach 2:
The patent uses feedback from data transfer completion status to control Alternate setting changeover timing. This feedback mechanism allows the system to optimize transmission efficiency through setting changes while preventing data loss by only allowing changes when appropriate.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3D
AI summary
In a case where a changeover request indicating to change over setting of an end point is received from an external apparatus, an information processing apparatus decides whether or not data is being transferred from the end point to a memory of the information processing apparatus. Then, in a case where it is decided that the data is being transferred from the end point to the memory, the information processing apparatus does not change over the setting of the end point.