Hi   I connect 7" hdmi display from waveshare to orange pi one on mainline dev kernel. http://www.waveshare.com/wiki/7inch_HDMI_LCD   When it is powered before orange, it works ok. But it don't work if it is powered at the same time.       I am tried to add hpd_delay at the top of  boot.cmd:   setenv video-mode sunxi:1024x768-24@60,monitor=hdmi,hpd=1,hpd_delay=20000,edid=1 saveenv   the do mkimage -C none -A arm -T script -d