After discovering this page I did some experimentation; connecting and disconnecting my iPhone 4 (ios 7.1.2) with up-to-date Ubuntu 16.10 using Unity running on a MacBookPro7,1

I found that just confirming **Trust** on the *iPhone* **had no effect**; \{ in fact I am asked repetitively to allow trust on this system but that is another matter }

I also found that *usbmuxd* is playing a big part in this problem, so forcing *usbmuxd* to exit is a quick and dirty fix.

 /usr/sbin/usbmuxd -X

After running the command I **can charge the phone**, and connect to it as a wireless or bluetooth hotspot without the cpu bandwidth consumption. { the phone also stops asking whether to trust the computer or not }

I hope this helps someone with more expertise than myself to devise a more acceptable fix for this.