Frame Buffer Copy for Partial Power Down Latency
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Solution Overview
Problem
Existing graphics subsystems face high power drain due to shared power rails, leading to decreased battery life, as components like memory devices continue to consume power even when not in use, and existing power-down methods introduce unwanted latency.
Innovation Solution
A system with a frame buffer and a dedicated copy buffer, where new image frames are opportunistically copied, allowing for partial power-down of memory devices except the first partition, which maintains display refresh using the dedicated copy buffer during low power mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If memory devices are powered down to save power, then power consumption is reduced, but latency increases due to wake-up time
Solution Approach 1:
The frame buffer is divided into multiple partitions, each mapped to separate memory devices. This allows selective power management where individual memory devices can be powered down independently based on their partition's usage, enabling granular power savings without complete system shutdown
Solution Approach 2:
A dedicated copy buffer stores pre-copied frame data before power-down occurs. The loader circuit proactively copies frame data from the frame buffer to the copy buffer in advance, ensuring that when memory devices are powered down, the display can continue refreshing from the pre-loaded copy without latency
Solution Approach 3:
Frame data is copied from the main frame buffer to a dedicated copy buffer that remains accessible during power-down states. This copy mechanism allows the display to continue operating from the copied data while the original memory devices are powered down, eliminating wake-up latency
2Loss of energy
If a multiple step method is used to detect duplicate frames and power down memory, then power savings are achieved, but system responsiveness decreases due to multiple stages
Solution Approach 1:
The duplicate frame detection function is extracted from the main processing flow and implemented as a dedicated circuit that operates independently and continuously. This allows detection to occur without interrupting normal display operations, maintaining system responsiveness while enabling power savings
Solution Approach 2:
A loader circuit acts as an intermediary between the frame buffer and display output. It continuously monitors for duplicate frames and manages the copying process to the dedicated copy buffer, enabling seamless power management without affecting the main system's responsiveness
Data Source
AI summary
Embodiments of the present invention may be directed to a graphics system of a computer system. The system may include a frame buffer having a number of partitions respectively mapped to a number of discrete memory devices and a dedicated copy buffer operable to store new image frames, mapped to a first memory device. The first memory device corresponds to a first partition of the number of partitions. The system may also include a loader circuit coupled between the frame buffer and the dedicated copy buffer, operable to copy new image frames from the frame buffer to the dedicated copy buffer. The system may also include a clocked output coupled to receive an image frame from the dedicated copy buffer and operable to drive a display device therewith. The system may enter a low power state wherein a number of the discrete memory devices are powered off.