I am not actually sure if this is an ARM problem or not but it only happens on my ARM Samsung 303c Chromebook.
After 10/15 mins or so X11 puts my notebooks screen to sleep (I have no idea if the whole system is suspended or just the screen whatever the default is); which is great, I want to save power.
however when I click the trackpad or press a key to wake it back up the black light comes on as does a blank screen. I have to force the system off by hold the power button down for 10 seconds.
I am running DWM desktop environment and the fbdev driver.