used to display memory usage successfully using the nvidia-smi command, but not recently,
NVIDIA-SMI has failed because it couldn’t communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running. And others said it is ok to install the driver again, these are not solve my problem, actually very simple question because ubutnu kernel update, a new version of the kernel and graphics driver does not match the above problems, we need only when making ubuntu startup guide interface, is just began to call you to select the operating system interface, select “ubuntu advanced options”, select a previous version of the kernel, is the new version of my 4.15.0-43 – generic
I then chose 4.15.0-42 – generic version, Then enter the system and use the nvidia-SMi command to execute successfully.
you can view the current ubuntu kernel version

using the following command

>uname -r