If anyone followed the advice of buying an XPS 13 and had magically appearing problems that sound wouldn’t work (although the OS thought it was working), I believe it was some kernel upgrade (if you install those)… upgrading to a 4.8 series kernel solved it for me.
Sorry, this is the most typical Linux thing I ever wrote and it makes me sad it happened to me for the first time in ~7 years of Linux usage when I use a Laptop meant to run Linux.
