Comment 97 for bug 1778011

@Alberto: Is there any chance that this work-around works without gdm3?
I'm using ubuntu-server 18.04 and this my laptop configuration:
➜ ~ inxi -G
Graphics: Card-1: Intel HD Graphics 5500
           Card-2: NVIDIA GK208M [GeForce 920M]
           Display Server: X.Org 1.19.6 driver: intel Resolution: 1366x768@60.06hz
           OpenGL: renderer: Mesa DRI Intel HD Graphics 5500 (Broadwell GT2) version: 4.5 Mesa 18.0.5

I followed the steps and installed required packages as follows:
➜ ~ sudo apt install nvidia-driver-390/bionic-updates ubuntu-drivers-common/bionic-proposed nvidia-prime/bionic-proposed nvidia-settings/bionic-updates libnvidia-gl-390/bionic-updates libnvidia-compute-390/bionic-updates libnvidia-decode-390/bionic-updates libnvidia-encode-390/bionic-updates libnvidia-ifr1-390/bionic-updates libnvidia-fbc1-390/bionic-updates

Then I executed "sudo prime-select nvidia".
But after rebooting, I have no openGl support and this error is present at Xorg's logs:
VGA arbiter: cannot open kernel arbiter, no multi-card support
Nvidia kernel modules are loaded and Xorg seems to register nvidia driver at init.

If I try to run glxgears for example, I get the following message:
glxinfo Error: couldn't get an RGB, Double-buffered visual

And using "sudo prime-select intel" also leaves me without GL. I think this is something related to gpu-manager, because I am not using any display manager, just running xorg from startx.