Comment 12 for bug 1719210

OK, I think I finally found the real trigger, helped by John Tanner's comment and Googling the bt_coex_active option. It's trying to simultaneously use bluetooth and a *2.4GHz* wifi network.

Trying that on my hardware results in lots of iwlwifi kernel logging reporting that the device microcode keeps crashing and requiring a hardware reset.

This happens both on 4.12 and 4.13, but 4.12 doesn't let it disrupt the bluetooth audio stream, so I didn't notice, but 4.13 kills the bluetooth connection.