For me the power management isn't working, too. The fan is always running and my notebook is getting hot.
I'm using Ubuntu 18.04 and installed the default nvidia driver 390.
My machine is an ASUS UX331UN with an nvidia mx150.
Currently my workaround is to install bbswitch and turn the nvidia graphics on/off with that by hand :/
For me the power management isn't working, too.
The fan is always running and my notebook is getting hot.
I'm using Ubuntu 18.04 and installed the default nvidia driver 390.
My machine is an ASUS UX331UN with an nvidia mx150.
Currently my workaround is to install bbswitch and turn the nvidia graphics on/off with that by hand :/