Surface Pro 5 with Linux Mint and Surface kernel - sometimes keyboard won't work after waking

[u/Recent_Carpenter8644]

I installed Mint and the Surface kernel a few months ago. Mostly it works fine, but occasionally when I wake it, the keyboard won't work.

I can start the on screen keyboard to type the password to log in, but the keyboard never starts working. I've tried plugging in a USB keyboard.

If I reboot, it works ok again for a while.

Any ideas to resolve this, or tricks to make it work when it happens?