LPD: Low Power Display Mechanism for Mobile and Wearable Devices

A plethora of mobile devices such as smartphones, wearables, and tablets have been explosively penetrated into the market in the last decade. In battery powered mobile devices, energy is a scarce resource that should be carefully managed. A mobile device consists of many components and each of them contributes to the overall power consumption. This paper focuses on the energy conservation problem in display components, the importance of which is growing as contemporary mobile devices are equipped with higher display resolutions. Prior approaches to save energy in display units either critically deteriorate user perception or depend on additional hardware. We propose a novel display energy conservation scheme called LPD (Low Power Display) that preserves display quality without requiring specialized hardware. LPD utilizes the display update information available at the X Window system and eliminates expensive memory copies of unvaried parts. LPD can be directly applicable to devices based on Linux and X Windows system. Numerous experimental analyses show that LPD saves up to 7.87% of the total device power consumption. Several commercial products such as Samsung Gear S employ LPD whose source code is disclosed to the public as open-source software at http://opensource. samsung.com and http://review.tizen.org.