I'm using the Pi Foundation 7" display (which I like very much) but have a problem. The display blanks after sitting idle, which is ok but if it sits too long it won't restore upon tapping it. I've searched the forums and see this topic with many confusing solutions. Can someone tell me what setting to change to stop this. I know the pi is still active because I can shell to it. What mode is it in, some special sleep mode? Nothing will bring the display back to life unless I reboot.