I have used the USB port on my Pro 3 to charge my phone forever. I travel with a cheap after market charger, that does not have a USB port. My phone charged just fine from the port, even when the Pro 3 was asleep. It would not charge of course in hibernate, as expected. Starting about two weeks ago, my phone now only charges, when the Pro 3 is awake. When asleep, the phone shows that it is charging, but it actually isn't. Or it is very very slowly. But the hardware has no trouble charging the phone when awake. A have also tried other cables. I have looked all over for some type of setting, maybe a power saver for when asleep. Anyone have any thoughts on where to look?