I followed the procedure in
https://bugzilla.redhat.com/show_bug.cgi?id=474477#c16
and it worked great for me; the built-in mic on my XPS M1530 works
reasonably (no more low mic) with skype in F10. I have to use
"alsamixer -c0" (text mode) for volume control, though;
gnome-volume-control did not show the new "DigitalMic" control for me.