System and technique for reducing power consumed by a data transfer operations during periods of update inactivity

摘要

A system and method are described that reduce display subsystem power consumption in computer systems where image data is transferred from an image memory to a display each time a new image frame is displayed. In normal operation, the computer system displays uncompressed image data, which is stored in the image memory. After a period of display inactivity, a display processor compresses the uncompressed data and writes the compressed data to another location in the image memory. In subsequent display cycles, until there is display activity, the display processor retrieves the compressed data from the memory, decompresses it in real time and then transfers the decompressed data to the display. Entire images or segments of images can be compressed in this manner. Using the compressed image data saves display power as it requires fewer memory cycles to transfer from the memory to the display than the uncompressed data. Bus bandwidth available for other, unrelated activities increases as the result of this bandwidth reduction, which benefits other system operations.