Dynamic FIFO Threshold Switching for Audio Power Management
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Solution Overview
Problem
Conventional High Definition Audio (HDA) systems face inefficiencies in power management, frequently exiting from deep sleep states to access system memory due to fixed FIFO threshold values, leading to excessive power consumption in portable devices.
Innovation Solution
Implementing a dynamic threshold switching mechanism for the FIFO buffer, allowing it to adjust between two threshold values based on the CPU's power state, ensuring sufficient data is maintained during state changes without under run or overrun, thereby optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed FIFO threshold value is used, then data under run or overrun is prevented, but the CPU frequently exits from deep sleep states to access system memory, leading to excessive power consumption
Solution Approach 1:
The patent applies dynamics by making the FIFO threshold variable rather than fixed. The threshold dynamically adjusts based on CPU power state: a first threshold is used when CPU is in active state, and a second threshold is used when CPU enters deep sleep state. This dynamic adjustment allows the system to maintain data integrity while reducing unnecessary memory accesses during low-power states.
Solution Approach 2:
The patent changes the threshold parameter based on CPU power state conditions. When CPU transitions to deep sleep state, the threshold parameter is changed from the first threshold to the second threshold, which is lower than the first threshold. This parameter change enables the CPU to remain in deep sleep state longer without risking data under run or overrun, thereby reducing power consumption.
2Use of energy by moving object
If a higher FIFO threshold is used, then the CPU can stay in power-saving states longer, but data under run or overrun may occur during state transitions
Solution Approach 1:
The system dynamically switches between different threshold values based on CPU state. When CPU is in deep sleep state, a lower second threshold is used to ensure data is fetched before under run occurs. When CPU transitions to active state, the higher first threshold is applied to prevent overrun. This dynamic switching maintains data integrity while enabling longer power-saving states.
Solution Approach 2:
The system performs preliminary actions by setting appropriate thresholds before CPU state transitions. Before entering deep sleep state, the system ensures sufficient data is in the FIFO buffer by using the first threshold for data collection. Before transitioning to active state, the system switches to the second threshold to prevent overrun during the transition period, ensuring data integrity is maintained throughout the state change.
3Use of energy by moving object
If the FIFO threshold is dynamically adjusted, then power consumption is reduced, but the system complexity increases
Solution Approach 1:
The threshold switching mechanism is integrated into the existing HDA controller architecture, making the controller multi-functional. The same controller handles both audio data processing and power management by automatically switching thresholds based on CPU state. This universality reduces overall system complexity despite the dynamic adjustment capability.
Solution Approach 2:
The system performs self-service by automatically detecting CPU power state and switching thresholds without external intervention. The HDA controller monitors CPU state and autonomously adjusts the FIFO threshold, eliminating the need for complex external control mechanisms. This self-service approach reduces system complexity while achieving power savings.
Data Source
AI summary
A system and method of dynamically switching the threshold of a data queue, such as FIFO, is disclosed. The data queue has a first threshold and a second threshold, wherein the first threshold is greater than the second threshold. The data queue is dynamically switched between the first threshold and the second threshold according to different power state of a central processing unit (CPU). A system memory is requested to fill the data queue with data whenever amount of the data queue is less than the switched first/second threshold.