Steps

1. Enable the following services in systemd:

   • nvidia-suspend.service

   • nvidia-resume.service

   • nvidia-hibernate.service

Enable via sudo systemctl enable <service name>.

1. Create a file named /etc/modprobe.d/nvidia-suspend.conf.

2. Add the following line to the file:

    options nvidia NVreg_PreserveVideoMemoryAllocations=1
   

3. Reboot

This shall prevent the cuInit: CUDA_ERROR_UNKNOWN: unknown error.

If that does not work

Execute the following:

sudo modprobe -r nvidia_uvm # or: sudo rmmod nvidia_uvm
sudo modprobe nvidia_uvm

Read more about the problem here.