Option to turn display off after locking screen.

[moilong]

Now the energy default config is dim, lock and then suspend after specified times. Can we change suspend_command so that instead of suspending it only turn off display and resume upon keypress.

[jbuchermn]

Take a look into the config options energy.idle_callback and energy.suspend_command. Should be possible by just leaving suspend_command empty and setting backlight to zero in idle_callback with e.g. "idle-presuspend".