A recent kernel upgrade caused my headphones to stop working. I asked on #alsa about this and after a lot of help from "debianuser" (thank you very much), he suggested I report this to this list.
I'm using x86-64 Fedora 22. The kernel that works is kernel-4.0.5-300.fc22.x86_64. The kernel that fails is kernel-4.1.3-200.fc22.x86_64. (These are the RPM package names in case that isn't clear.)
The output from alsa-info.sh for the working case:
http://www.alsa-project.org/db/?f=1da69e358935e2d4a35513fc308a74a07925a4fd
... and for the failing case:
http://www.alsa-project.org/db/?f=6a1439affc507f1b83f99b5f42b7cbfe0664f9e8
I'm happy to provide other information as needed, though you'll have to tell me exactly what to do, and turnaround may be on the slow side.
thanks, Tom