Hi I brought a Redmi Notebook 14 (2019) and found the internal mic doens't work with Ubuntu 18.04 kernel 5.0.
Both internal and external mic didn't work.
It works with Window10 which came as the default OS, but I needed Linux so I install an Ubuntu 18.04 LTS.

I raised a bug with Canonical and had some discussion with its Engineers.

The conclusion is as follows:
1. we need to set some coeff to make the internal mic work, but only Realtek engineers know how to set the coeff registers.

2. there is no change for external mic plugging, and this requires Redmi to ask for help from realtek.

It's okay if this issue can't be fixed for 18.04 as I'm happy to have a patch or have it fixed in the future Ubuntu versions, but I'd like to ask if you could help to get this one fixed.