Patent ID: 6950105

Claim:
A method for reducing power consumption for a portable device employing a graphics processing circuit comprising: determining, by a processor, graphics processing requirements of said graphics processing circuit from, at least one display mode setting for a display device; varying, under control of the processor, the frequency of at least one clock source used by said graphics processing circuit so as to substantially match the speed of said at least one clock source to graphics processing requirements; determining when the power source for said graphics processing circuit has changed from an A.C. source to a battery; selecting a lower frequency for the at least one clock source that is less than its frequency prior to when the power source changed to a battery including; determining required frame buffer access bandwidth based on at least one of display mode setting data and whether a hardware overlay surface has been allocated; comparing the required frame buffer access bandwidth to the frame buffer access bandwidth provided by the lower frequency for the at least one clock source; and increasing the frequency for the at least one clock source until the frame buffer access bandwidth provided by the increased frequency matches the required frame buffer access bandwidth.