Comment # 1 on bug 1219147 from Takashi Iwai

A known regression, some info found in bsc#1218948 (although the original issue
of that bug entry is different from your issue).
The latest SLE15-SP5 git branch already contains the fix.  Try the kernel in
OBS Kernel:SLE15-SP5 repo
  http://download.opensuse.org/repositories/Kernel:/SLE15-SP5/pool/