[Debian testing] Works under GNOME but not an alternate window manager (StumpWM)

[tsmacdonald]

Hello, I have a brand new install of Debian testing. Installing displaylink-debian went fine, and on GNOME everything is working as expected with my internal laptop screen and two external monitors (both connected to the same hub). Here's my debug output (not the number of xrandr providers is 0).

Click for debug output on GNOME

--------------- Linux system info ----------------

Distro: Debian
Release: trixie
Kernel: 6.11.7-amd64

---------------- DisplayLink info ----------------

Driver version: 1.14.7
DisplayLink service status: up and running
EVDI service version: 1.14.7

------------------ Graphics card -----------------

Vendor: i915
Subsystem: [103c:8b41]
VGA: Intel Corporation Raptor Lake-P [Iris Xe Graphics] (rev 04)
VGA (3D): 
X11 version: 21.1.14-1
X11 configs: /etc/X11/xorg.conf.d/20-displaylink.conf /etc/X11/imwheel/startup.conf

-------------- DisplayLink xorg.conf -------------

File: /etc/X11/xorg.conf.d/20-displaylink.conf
Contents:
 Section "Device"
    Identifier  "Intel"
    Driver      "intel"
EndSection

-------------------- Monitors --------------------

Providers: number : 0

However, when running StumpWM instead of Gnome, only the internal laptop screen works. arandr doesn't see the external displays. I've already tried reinstalling displaylink-debian from under StumpWM, so I'm not quite sure what to do:

--------------- Linux system info ----------------

Distro: Debian
Release: trixie
Kernel: 6.11.7-amd64

---------------- DisplayLink info ----------------

Driver version: 1.14.7
DisplayLink service status: up and running
EVDI service version: 1.14.7

------------------ Graphics card -----------------

Vendor: i915
Subsystem: [103c:8b41]
VGA: Intel Corporation Raptor Lake-P [Iris Xe Graphics] (rev 04)
VGA (3D): 
X11 version: 21.1.14-1
X11 configs: /etc/X11/xorg.conf.d/20-displaylink.conf /etc/X11/imwheel/startup.conf

-------------- DisplayLink xorg.conf -------------

File: /etc/X11/xorg.conf.d/20-displaylink.conf
Contents:
 Section "Device"
    Identifier  "Intel"
    Driver      "intel"
EndSection

-------------------- Monitors --------------------

Providers: number : 1
Provider 0: id: 0x4a cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 5 outputs: 7 associated providers: 0 name:Intel

[tsmacdonald]

The key variable here seems to be that GNOME (working) is running on Wayland but Stump (not working) is running on X. Since the post-install guide says

When you are logging into your session [make sure] you are using X server (X11) and not Wayland.

I was sort of thinking it would be the opposite. Is the driver only supported on Wayland?