Impact: The upstream process for stable tree updates is quite similar in scope to the Ubuntu SRU process, e.g., each patch has to demonstrably fix a bug, and each patch is vetted by upstream by originating either directly from Linus' tree or in a minimally backported form of that patch.
The 18.104.22.168 upstream stable patch set is now available and contains fixes for this problem. It should be included in the Ubuntu kernel as well.
Related commits in the Lucid repo are:
8ad8264 ALSA: hda: Use LPIB for an ASUS device