[SOLVED] Cannot access secondary GPU - error: [XORG] (EE) Failed to load module "nvidia" (module does not exist, 0)

$ optirun -b none nvidia-settings -c :8
[   70.861063] [ERROR]Cannot access secondary GPU - error: [XORG] (EE) \

Failed to load module "nvidia" (module does not exist, 0)

[   70.861138] [ERROR]Aborting because fallback start is disabled.

The above is the problem I've encountered recently during NVIDIA proprietary driver installation on Fedora 31. Here're some details about a kernel and graphics card:

$ uname -r
5.4.13-201.fc31.x86_64

$ lspci -vnn | grep '\''[030[02]\]'
00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core \

processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])

01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GK107M \

[GeForce GT 650M] [10de:0fd1] (rev ff) (prog-if ff)

I followed these instructions - https://docs.fedoraproject.org/en-US/quick-docs/bumblebee/index.html#_installation_nvidia_proprietary_driver. But after system restart "nvidia" module failed to load.

Here's a good troubleshooting page - https://github.com/Bumblebee-Project/Bumblebee/wiki/Troubleshooting. But there was nothing related to the mentioned error.

After reviewing bumblebee config I found out that "nvidia" module was actually missed:

$ grep "XorgModulePath" /etc/bumblebee/bumblebee.conf 
XorgModulePath=/usr/lib64/nvidia/xorg,/usr/lib64/xorg/modules

$ find /usr/lib64/xorg/modules -iname *nvidia*
$

Installing nvidia-driver and restarting the system solved the problem:

$ sudo dnf install nvidia-driver

$ find /usr/lib64/xorg/modules -iname *nvidia*
/usr/lib64/xorg/modules/drivers/nvidia_drv.so
/usr/lib64/xorg/modules/extensions/libglxserver_nvidia.so