How to turn off your monitor

# setting "true" or "1" can activate monitor off option
setenv monitor_onoff "true"

# Boot Arguments
setenv bootargs ${bootargs} monitor_onoff=${monitor_onoff}

[system] -> [preference] -> [look and feel] -> [Screensaver] 
[Power Management] tab in the bottom area of this menu

For example, if you set screensaver time to 1 minute and display off time to 5 minutes in Power Management tab,

- in 1 minute, display will be turned off and screensaver is activating but, monitor is still alive.

- in 5 minutes, monitor will be turned off.

The env description, “suspend_hdmiphy” is included in boot.ini of Android release version as following.

# Overscan offset configuration
# All offsets are zero and can be tuned by manual or ODROID Utility
setenv overscan_top "0"
setenv overscan_left "0"
setenv overscan_bottom "0"
setenv overscan_right "0"
setenv suspend_hdmiphy "true" # set "true" of "1" to activate monitor off option
led_blink=1


# Boot Arguments
setenv bootargs "${rootopt} ${consoleopt} hdmimode=${hdmimode} hdmitx=${cecconfig} vout=${vout_mode} disablehpd=${disablehpd} logo=${logoopt} ${androidopt} ${selinuxopt} suspend_hdmiphy=${suspend_hdmiphy} led_blink=${led_blink} max_freq=${max_freq} maxcpus=${maxcpus}"

You can set the standby time to enter sleep and monitor off using display setting menu.

settings -> display -> sleep -> set sleep time

For example, if you set the sleep time to 5 minutes, your monitor will be turned off in 5 minutes.