安装显卡驱动时报错:
ERROR: An NVIDIA kernel module ‘nvidia-drm’ appears to already be loaded in your kernel. This may be because it is in use (for example, by an X server, a CUDA program, or the NVIDIA Persistence Daemon), but this may also happen if your kernel was configured without support for module unloading. Please be sure to exit any programs that may be using the GPU(s) before attempting to upgrade your driver. If no GPU-based programs are running, you know that your kernel supports module unloading, and you still receive this message, then an error may have occured that has corrupted an NVIDIA kernel module’s usage count, for which the simplest remedy is to reboot your computer.

解决方法:
https://blog.csdn.net/xunan003/article/details/81665835

CUDA Installation

1. Download the latest CUDA Toolkit

2. Switch to tty3 by pressing Ctl+Alt+F3

3. Unload nvidia-drm before proceeding.

3a) Isolate multi-user.target

sudo systemctl isolate multi-user.target
3b) Note that nvidia-drm is currently in use.

lsmod | grep nvidia.drm
3c) Unload nvidia-drm

sudo modprobe -r nvidia-drm
4d) Note that nvidia-drm is not in use anymore.

lsmod | grep nvidia.drm
5) Go to your download folder and run the cuda installation.

sudo sh cuda_10.1.168_418.67_linux.run
6) Answer any prompts during installation.

7. When installation has finished, confirm that the CUDA Version has been updated.

nvidia-smi
8) Start the GUI again.

sudo systemctl start graphical.target