I have the same problem upon turning on Ubuntu 18.04 with Nvidia 2070 Super. While I turn off the Ubuntu 18.04 and turn on it again. It goes back to the normal state. It is just like a bug for the Ubuntu 18.04 system with Nvidia Driver.
It is necessary to address that nvidia-430 ppa is not accepted by RTX 2070 super. Nvidia has closed the opportunities of nvidia-430 ppa installation. The system automatically gives the Nvidia-440 ppa for installation.
I have the following installation steps
1. Add the Nvidia ppa repo
$ sudo add-apt-repository ppa:graphics-drivers/ppa
$ sudo apt-get update
3. Install Nvidia driver
$ sudo apt install nvidia-driver-440
4. Reboot Ubuntu 18.04
$ sudo reboot
5. Check the Driver
It has still has the problem sometimes.
Please indicate how to solve it completely.
Thanks in advance,
While I met the problem with RTX 2060 several month ago, I installed nvidia-driver-430 ppa, it solve the issue. However, while I had RTX 2070 Super this week, I could not be allowed to install nvidia-driver-430 ppa, Therefore, the error occurs again. And it seems that I have no better way to solve it this time. nvidia-driver-440 ppa has a problem with Ubuntu 18.04 but it is forced by Nvidia.