A friend brought me their Samsung S7 with a broken screen asking if I could recover their data.
The display was non-functional, as well as the USB port. They had been wirelessly charging until the screen gave up the ghost.
Step 1: Fix USB port
It was just dirt and grime inside the port that didn't let the plug properly seat. Using some graduated needles (sold as tools for cleaning 3d printer nozzles) is my method for cleaning. altho cutting a piece of plastic of an appropriate thickness is the cheap and easy way.
Now the phone was charging, and would turn on (vibrated and led activated).
Step 2: Access?
The phone defaults to "Charge Only" mode on usb. I confirmed with
lsusb. USB Debugging mode was never endabled.
I couldn't boot into ODIN mode, as it had a bootloader locked by VZW.
Supposedly a Samsung Account can remotely unlock a phone. My friend has an account and thats the best plan of action.
The only other ideas are repairing the screen, or hooking a USB-OTG keyboard up and trying to blindly unlock it and enable MTP transfer.