Unable to get PRIME listed in Nvidia X Server Settings under Ubuntu Linux 18.10 on Thinkpad X1 Extreme

Thanks. Where is xorg.conf located? Some mentioned that is is not longer used?

The better place would be inside the outputclass section in
/usr/share/X11/xorg.conf.d/10-nvidia.conf

Thanks. I looked into /usr/share/X11/xorg.conf.d/ There is no 10-nividia.conf. So I will create it. In this case, am I correct that I just need to put the following exactly (including the word Option) in the file? After doing that, do I need to reboot?

Option “RegistryDwords” “EnableBrightnessControl=1;”

Odd. That’s a standard file that normally gets installed along with the driver.
Instead, create a file /usr/share/X11/xorg.conf.d/12-nvidia.conf

Section "OutputClass"
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "AllowEmptyInitialConfiguration"
    Option "RegistryDwords" "EnableBrightnessControl=1;" 
    ModulePath "/usr/lib/x86_64-linux-gnu/nvidia/xorg"
EndSection

In that folder, I only have: 10-amdgpu.conf,10-quirks.conf, 10-radeon.conf, 40-libinput.conf, 70-wacom.conf

Maybe that file now only gets created if you install the driver from ppa. Doesn’t matter, just create it.

Still does not work. Things that I have changed are:

  1. Inside /etc/default/grub modified the line GRUB_CMDLINE_LINUX_DEFAULT as follows:
    GRUB_CMDLINE_LINUX_DEFAULT=“quiet splash acpi_backlight=vendor”

    executed: sudo update-grub and rebooted

  2. Created a file /etc/modprobe.d/99-nvidia-backlight.conf
    Put: options nvidia NVreg_EnableBacklightHandler=1
    inside the file and
    executed: sudo update-initramfs -u

  3. Created a file /usr/share/X11/xorg.conf.d/12-nvidia.conf
    Put the following in the file:

    Section “OutputClass”
    Identifier “nvidia”
    MatchDriver “nvidia-drm”
    Driver “nvidia”
    Option “AllowEmptyInitialConfiguration”
    Option “RegistryDwords” “EnableBrightnessControl=1;”
    ModulePath “/usr/lib/x86_64-linux-gnu/nvidia/xorg”
    EndSection

    Rebooted

I reinstalled Ubuntu 18.10. Under Software & Update->Additional Drivers, there are two options:

NVIDIA Corporation: GP107M [GeForce GTX 1050 Ti Mobile]

Using NVIDIA driver metapackage from nvidia-driver-390 [proprietary, tested]
Using X.Org X server - Nouveau display driver from xserver-xorg-video-nouveau (open source)

Which one should I choose? Currently, it is “No proprietary drivers are in use”

You should install the nvidia-driver-390. Though I’d rather recommend that you go with 18.04, at least there the most bugs and workarounds are known since your Thinkpad seems quite problematic with Linux.

I encounter the same problem. @gtxlaptop have you solved it?