Monitor does not show up in xrandr

[rcw]

Hello, I'm trying to get a Wavlink WL-UG39DK1-BL Rev C1 with Planar PL1910M monitor connected via DVI to work on Debian 9. I'm currently using the 4.16 Squeeze Backports kernel, but could downgrade to 4.9 if necessary. I've used the installer at https://github.com/AdnanHodzic/displaylink-debian.

It seems like I'm very close to having this working. The modules build correctly. The dlm service starts and runs. The evdi module loads. I see the EDID and modelines output for the new DVI-I-1-1 output under $HOME/.local/share/xorg/Xorg.0.log. However, this DVI-I-1-1 output does not show up anywhere else - not in xrandr or ARandR, and I cannot find a way to enable it as an additional screen. The monitor remains in power-save mode.

This output is the same with or without the Wavlink attached:
$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x76 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 3 outputs: 3 associated providers: 0 name:modesetting
Provider 1: id: 0x41 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting
$ xrandr --listmonitors
Monitors: 1
0: +*DP-1 1280/380x1024/300+0+0 DP-1

I've attached the DLSupporttool output as well as the Xorg.0.log file from my home directory which the support tool did not find.

Hopefully I'm missing something simple.