I updated to tumbleweed from 13.2
When I reboot, there is no sound configured, just a dummy device.
I opened yast and I can play the test sound from yast>Hardware>Sound.

I changed the preferred order of the sound cards in the list and hit Ok,
and the sound devices appeared in the system.

I had to reboot (because of different problem) and had no sound again.
I changed the preferred order of the sound cards in the list and hit Ok,
and the sound devices again appeared in the system.

There's something that fixes the sound when configured by yast that does not
work from boot.

I found BZ#972315 that affected this area (3.1.9), but I'm running 3.1.10
i | yast2-sound             | package | 3.1.10-1.2 | x86_64 | tw-oss