System and technique for reducing power consumed by a data transfer operations during periods of update inactivity
DC CAFCFirst Claim
1. A data interface system, comprising:
- a processing unit configured to receive input data from a memory and generate from the received input data corresponding output data;
an uncompressed version of the input data, which is stored in the memory; and
a compressed version of the input data, which is stored in the memory;
such that;
the processing unit is configured, when the input data has not been recently updated, to generate the compressed version from the uncompressed version and to generate the output data from the compressed version; and
the processing unit is configured, when the input data has been recently updated, to use at least a subset of the uncompressed version to generate the output data.
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Abstract
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.
116 Citations
31 Claims
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1. A data interface system, comprising:
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a processing unit configured to receive input data from a memory and generate from the received input data corresponding output data; an uncompressed version of the input data, which is stored in the memory; and a compressed version of the input data, which is stored in the memory; such that; the processing unit is configured, when the input data has not been recently updated, to generate the compressed version from the uncompressed version and to generate the output data from the compressed version; and the processing unit is configured, when the input data has been recently updated, to use at least a subset of the uncompressed version to generate the output data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A data interface method, comprising the steps of:
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receiving input data from a memory; determining whether the input data has been recently updated; generating, when at least a subset of the input data has not been recently updated, a compressed version of the subset of the input data; and generating, as long as the subset is not subsequently updated, corresponding output data from the compressed version of the subset. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification