Sleep function

[mat02]

Hi!
I'm trying to invoke sleep mode from my app to save battery. However, inkview.Sleep() returns immediately (both normal and deep option) and doesn't appear to do anything.
I tried calling it from coroutines, from main event handler and even from main event loop handler wrapper in C, but the result is the same. IsTaskActive, when checked right before invoking sleep, returns 1. SleepMode also returns nonzero value.
Does anyone know what is the correct sequence to invoke sleep?
My usecase is that I only need to refresh data once in an hour or so (displaying calendar agenda). I thought that I could put the device to sleep in-between updates and extend the battery life.

[SUNsung]

If you fall asleep, you will not be able to wake up. When you fall asleep, all processes are put on hold.

You can simply do nothing; there is no background screen refresh (unless you implement it), so until there are events (button, sensor), the device ‘waits’.
I recommend only turning off the internet while waiting, as it consumes the most power.