nvidia driver downgrade/재설치

1. nvidia driver matching 버전 확인
 cuda-compatibility 버전 확인(https://docs.nvidia.com/deploy/cuda-compatibility/)

2. nvidia driver 삭제

$ sudo apt-get remove --purge nvidia-*
$ sudo apt-get autoremove
$ sudo apt-get update
$ reboot

3. driver 확인

$ ubuntu-drivers devices

4. Repository 추가 및 driver 설치

$ sudo add-apt-repository ppa:graphics-drivers/ppa
$ sudo apt update
$ sudo apt-get install nvidia-driver-[Version Number]
$ reboot