GTX 1660 eGPU/Ubuntu 18.04 Drivers Running, Monitor Detected, No Signal

I’ve been having a heck of a time getting my GTX 1660 to work with Ubuntu 18.04 on my LG Gram 17 (Thunderbolt 3 connection). The drivers seem to be working just fine: nvidia-smi gives an appropriate output and lspci -k lists nvidia as the driver for the VGA component of the graphics card. When I go to displays to switch from single display to join displays, it accurately shows my external monitor as an HP with accurate size, etc. When I select join displays and hit apply, it blinks and prompts to either keep or revert changes, but no actual change has occurred. I don’t think it’s a hardware issue: card and monitor work just fine in Windows 10 with the same set-up; and I was able to get just the external monitor to work by creating a xorg.conf.d directory in /etc/X11 and nvidia.conf in that directory with the following contents:

Section "Device"
        Identifier      "Videocard0"
        BusID           "PCI:06:0:0" 
        Driver          "nvidia"
        VendorName      "NVIDIA Corporation"
        Option          "AllowEmptyInitialConfiguration"
        Option          "AllowExternalGpus"

Like I said, this enabled the external monitor, but left the LG’s internal monitor useless whether or not the eGPU was plugged in. Deleting the file and directory reverted this.

There are two things I’ve noticed that seem off:

  1. nvidia-settings yields

    ERROR: Unable to load info from any available system

  2. xrandr --listproviders yields:

    Providers: number : 2
    Provider 0: id: 0x47 cap: 0x9, Source Output, Sink Offload crtcs: 3 outputs: 5 associated providers: 1 name:modesetting
    Provider 1: id: 0x263 cap: 0x2, Sink Output crtcs: 4 outputs: 4 associated providers: 1 name:modesetting

Is it weird for them to both be named “modesetting”?

Let me know if there are any other details that may be helpful!

nvidia-bug-report.log.gz (2.3 MB)
Note: Like I said, I’ve had a heck of a time getting this far, so the bug report is a bit of a mess, but I do think that the driver loading issues are fixed. Someone who knows more than me might know better though.