The Linux ttyACM0 drama - more details after a lot of experimenting

Using Arduino IDE 1.x
30

stimmer:
I notice linux is using xhci - are you on a USB3 port? If your computer has any USB2-only ports try using those instead.

Aft much stuffing about, using a USB2 hub on a USB3 port did the trick for me. Thank you for restoring my sanity.