Startup - Black screen with blinking cursor, only while docked...

[rdkls]

I have Kubuntu 18.04 installed on a Thinkpad P51 with an Nvidia Quadro M2200 and an Intel P630 (Optimus) using the NVIDIA proprietary driver 390.48.

derek@ds-p51:~$ lspci | egrep 'VGA|3D'
00:02.0 VGA compatible controller: Intel Corporation HD Graphics P630 (rev 04)
01:00.0 3D controller: NVIDIA Corporation GM206GLM [Quadro M2200 Mobile] (rev a1)

Problem: After configuring options nvidia_drm modeset=1 in /etc/modprobe.d/zz-nvidia-modeset.conf to clean up screen-tearing issues, my laptop sits at a black screen with a blinking cursor in the upper left corner of the screen, but only when I start it while docked. If I eject it from the dock it quickly proceeds to the login screen. This does not happen if I start without the dock, or remove the modeset configuration.

Other info: There are two external displays connected to the dock, and another connected directly to the laptop via USB-C; workstation.

[GreyGeek]

Can you reach a terminal from there? (Ctl+Alt+F2).
If so, try
sudo systemctl restart sddm

[rdkls]

I tried sudo systemctl restart sddm from tty2 but this did not move things along (going back to tty1).

Interestingly enough I found out this morning that if I let it sit for 3-5 minutes (bathroom, coffee), it'll eventually proceed to the login screen; albeit a login screen with inception (screenshot to come). Basically the laptop LCD is showing the login screen, and so is the USB-C attached 4K display in the middle; but the 4K display shows it at 4K resolution, as well as 1080p overlaying the 4K login screen in the upper left corner.