Detecting whether the screen is updating. If it isn't, delegate composition to GLES instead of the HWC to save power.
Implement an item from https://source.android.com/devices/graphics/implement-hwc , 'Optimize the HWC' section:
- Detecting whether the screen is updating. If it isn't, delegate composition to GLES instead of the HWC to save power. When the screen updates again, continue to offload composition to the HWC.
There is already implementation of similar feature added by !3 (merged) , but unfortunately not all hardware have write-back implemented on the kernel side. Using the method recommended by Google would cover all the hardware.