I've experienced this issue running kernel 4.17-rc5 on Fedora 28, but other users have reported it on 4.16.x. I have an XPS 13 9370, and it hits me almost daily. It's also reported against the 9360 and the Precision 5520. (One user even mentioned he experienced it on a Lenovo. So not necessarily a Dell specific issue, but the majority of the reporters are on Dell machines.)
Basically, sometimes the laptop loses the wifi signal completely, after that we turn the wifi off and on again, and when turning it on again the whole system simply hangs.
Has anyone here encountered this issue? What could be the possible fix?
This could be related to this as I have the same problem in combination when bluetooth completely crashes (WIFI also gone sometimes):
And no fix available, yet.
No, it is not related to bluetooth at all. This is just a mistake in the ath10k kernel driver. The fix is already ready, just not yet accepted in the upstream kernel. (Which will not affect the Bluetooth device, of course.)