The patch described in comment #6 has landed upstream in 4.18, so the next step would be to backport to 4.15 Ubuntu kernel so that it was available in the 16.04.5 HWE kernel.
The patch described in comment #6 has landed upstream in 4.18, so the next step would be to backport to 4.15 Ubuntu kernel so that it was available in the 16.04.5 HWE kernel.