Comment # 13 on bug 1179951 from Takashi Iwai

Hm, OK, then this might be a different issue from what I've seen in the past.

Currently I have no idea.  You can try Leap 15.1 kernel on top of the 15.2
system and see whether the same problem still happens.  You might need to
replace kernel-firmware-* packages with the old kernel-firmware for that, but
the rest should work with Leap 15.1 kernel.

If Leap 15.1 is confirmed to work, you can try to narrow down the kernel
version showing the regression by trying various kernels in my OBS repo, OBS
home:tiwai:kernel:4.13, home:tiwai:kernel:4.14, etc.