现象是RK3399在10分钟左右会关闭HDMI

cd /etc/X11/xorg.conf.d

vim 20-modesetting.conf

文件下方新增以下内容

Section "ServerFlags"
#other options can go here
Option "BlankTime"   "0"
Option "StandbyTime"  "0"
Option "SuspendTime"  "0"
Option "OffTime"  "0"
EndSection