MST Docking station, how to configure, who talks to the Billboard device?

Dear friends,

i am using ThinkBook P16 with 2 USB-C (with Alt-DP 1.4
Support). On this ground i purchased a MST Docking-Station,
in order to deliver 3 4K Monitors with a DP Signal.
Under W10 this works perfectly, well the configuration
was a bit tricky, because i had overseen to configure my
monitors with 30Hz/60Hz/30Hz due to the limited bandwith.

I wanted the same for the Linux, using no driver meant "no driver issue" to me, but ... i was wrong!
I connected the MST-Dockingstation with my notebook and expected some monitors appear in:

Code:$ xrandr -q
Screen 0: minimum 320 x 200, current 2560 x 1600, maximum 16384 x 16384
eDP connected primary 2560x1600+0+0 (normal left inverted right x axis y axis) 344mm x 215mm
2560x1600 60.03*+ 48.02
1920x1200 60.03
1920x1080 60.03
1600x1200 60.03
1680x1050 60.03
1280x1024 60.03
1440x900 60.03
1280x800 60.03
1280x720 60.03
1024x768 60.03
800x600 60.03
640x480 60.03
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)This is ok, because it shows onyl the notebook monitor and its 2 DP sockets, that are not connected (yet).
Next lsusb gives me this:

Code:$ lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 003: ID 048d:c916 Integrated Technology Express, Inc. ITE Device(8296)
Bus 003 Device 002: ID 04f2:b71f Chicony Electronics Co., Ltd Integrated Camera
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 004: ID 05e3:0749 Genesys Logic, Inc. SD Card Reader and Writer
Bus 002 Device 005: ID 0bda:8153 Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter
Bus 002 Device 003: ID 2109:0815 VIA Labs, Inc. USB3.0 Hub
Bus 002 Device 002: ID 2109:0817 VIA Labs, Inc. USB3.0 Hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 04f3:0c4b Elan Microelectronics Corp. ELAN:Fingerprint
Bus 001 Device 003: ID 8087:0029 Intel Corp. AX200 Bluetooth
Bus 001 Device 007: ID 2109:8888 VIA Labs, Inc. USB Billboard Device
Bus 001 Device 009: ID 046d:0825 Logitech, Inc. Webcam C270
Bus 001 Device 011: ID 0557:2407 ATEN International Co., Ltd USB 2.0 Peripheral Switch
Bus 001 Device 013: ID 046d:c53d Logitech, Inc. G631 Keyboard
Bus 001 Device 012: ID 046d:c539 Logitech, Inc. USB Receiver
Bus 001 Device 010: ID 2109:2813 VIA Labs, Inc. VL813 Hub
Bus 001 Device 008: ID 0409:005a NEC Corp. HighSpeed Hub
Bus 001 Device 006: ID 2109:2815 VIA Labs, Inc. USB2.0 Hub
Bus 001 Device 005: ID 0d8c:0014 C-Media Electronics, Inc. Audio Adapter (Unitek Y-247A)
Bus 001 Device 002: ID 2109:2817 VIA Labs, Inc. USB2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hubThis looks ok, we have to look at the device ID 2109:8888 VIA Labs, Inc. USB Billboard Device.
If your dig through the USB-Tree (call lssusb -t -v) you will notice that this node is used to control the counterpart of my notebooks Alt-DP inside the docking station.

The difference between a cable that connect "USB-C Alt-DP" directly with a monitor with a DisplayPort port and MST station can be understood with the fixed modes of the connected monitor, its resolution and the supported frequencies. (also known as single display).
MST is different, its aim is to cut the canvas of a 5K Display with 60Hz to 2 or more monitors. So we may expect a chip with some logic, that distributes the signal to some devices and the job of thw USB Billboard Device is to configure the device.

So my question is: who is responsible for this?
Please note, that the device is capable to split up and distribute the signal flow of a 60Hz 5K display on 3 4K Monitors 2*4K monitors running at 30Hz and another one running with 60Hz. You can also feed different monitors with different resolutions and frequencies.

So who the hell is responsible for the configuration, who talks to the Billboard node via USB?