I'm entering deep sleep using
echo mem > /sys/power/state
I then try to exit by using one of the UARTs. I enable it using
echo enabled > /sys/devices/platform/30880000.serial/tty/ttymxc2/power
and then just send characters via usb to the UART from a host machine. This all works fine if I put the board into what I assume is the system idle state using
echo freeze > /sys/power/state,
but not with the deep sleep state (I never get access to the terminal, it just hangs). I'm sure the UART connection is all fine as I can communicate to and from the device using it. I have also tried using usb to trigger wake events but with no luck. The board has no power button, but does have USB, UART, ethernet, and GPIO.
Can anyone offer any suggestions as to why this would work putting it into the freeze state, but not the deep sleep state? Would this be more likely to work with GPIO pins instead?
Many thanks for your time.