a simple tip to pass on, waking up blackened screen during phone call

[davehorne]

It's infuriating when you're on hold during a phone conversation and the screen goes black.

You tap the screen, and nothing.

I just had to Google this and it appears a double tap is the procedure to bring back a blackened screen during a phone call.

This is a well hidden option.  Settings (not settings from within Phone, but primary Settings) \ Advanced features \ Motions and gestures \ Double tap to wake.