Bug#953366: nvidia-kernel-dkms: module not loaded due lockdown

[mando at april.org]

Dear maintainers,

My problem is solved.

It was happening because I did signed nvidia-kernel.ko as explained here in:
https://wiki.debian.org/SecureBoot

In the details, to automate the process for future nvidia-kernel-dmks 
update, I relied on this link:
https://gist.github.com/dop3j0e/2a9e2dddca982c4f679552fc1ebb18df

So, I generated my MOK key, rebooted my computer to enroll it, and 
created /etc/dkms/nvidia-current.conf containing:

POST_BUILD=../../../../../../root/module-signing/dkms-sign-module

Then, I installed optirun and nvidia-smi:

apt install primus nvidia-smi

... rebuilt the nvidia module and

apt reinstall nvidia-kernel-dkms

... and provided the passphrase of my MOK key (see dkms-sign-module) 
when prompted.

After reboot, the nvidia module is now correctly loaded:

(mando at aldur) (~) $ lsmod | grep nvidia
nvidia_drm             53248  0
nvidia_modeset       1118208  1 nvidia_drm
nvidia              20467712  19 nvidia_modeset
ipmi_msghandler        65536  2 ipmi_devintf,nvidia
drm_kms_helper        212992  2 nvidia_drm,i915
drm                   548864  13 drm_kms_helper,nvidia_drm,i915

In the details, if I run:

optirun glxgears

... and nvidia-smi in another terminal, I get:

(mando at aldur) (~) $ nvidia-smi
Tue Apr 14 03:58:29 2020
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 440.64       Driver Version: 440.64       CUDA Version: 
N/A      |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile 
Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  
Compute M. |
|===============================+======================+======================|
|   0  GeForce MX150       On   | 00000000:02:00.0 Off 
|                  N/A |
| N/A   46C    P0    N/A /  N/A |     10MiB /  2002MiB | 4%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
|  GPU       PID   Type   Process name                             
Usage      |
|=============================================================================|
|    0      2306      G /usr/lib/xorg/Xorg                             
7MiB |
|    0      2310      G glxgears                                       
2MiB |
+-----------------------------------------------------------------------------+

Best regards, you can close the bug

mando