Maybe some more practical infos:
You have a hybrid amd/nvidia system so you can’t/mustn’t use nvidia-xconfig, you’ll never get a working config out of it. In general, nvidia-xconfig shouldn’t be used on modern systems.
The problem with Ubuntu’s prime-select feature is it (still) doesn’t work for amd/nvidia but only for intel/nvidia. Needs manual tweaking of the config files.
You could try this:
Please delete /etc/X11/xorg.conf
and modify /usr/share/X11/xorg.conf.d/10-amdgpu.conf
replacing only
Driver "amdgpu"
with
Driver "modesetting"
Please add
Option "PrimaryGPU" "Yes"
inside the OutputClass of /usr/share/X11/xorg.conf.d/10-nvidia.conf
Then create two files optimus.desktop in /etc/xdg/autostart/ and /usr/share/gdm/greeter/autostart/ containing
[Desktop Entry]
Type=Application
Name=Optimus
Exec=sh -c "xrandr --setprovideroutputsource modesetting NVIDIA-0; xrandr --auto"
NoDisplay=true
X-GNOME-Autostart-Phase=DisplayServer
This should enable the nvidia profile on Ubuntu.
The “render offload” feature needs a patched Xserver, I don’t know if Ubuntu is providing this. If so, it could be enabled by not doing any of the above mentioned settings, but by creating an /etc/X11/xorg.conf just containing
Section "ServerLayout"
Identifier "layout"
Option "AllowNVIDIAGPUScreens"
EndSection
Afterwards, function can be checked running
__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia glxinfo | grep vendor
should return something “Nvidia”.
Then applications can be started on the nvidia gpu running
__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia
Downside of this is that no external monitors connected to the nvidia gpu will work.