It seems the microphone doesn’t work out of the box on the XPS 13 “Developer Edition”. Worse, you’ll actually need to re-compile your kernel to make it work… at least the patches are easy to find thanks to Dell’s “Project Sputnik” leader Barton George:
I used those on the Linux 4.0.2 (stable) kernel, recompiled, installed… and voilà! The microphone works!
Hopefully those fixes will soon be in the kernel main line…
