How to make a KVM (built into the monitor) connection work , using a DisplayPort/Usb-C cable connected to a thinkpad dock

In this setup, the other device connected to the KVM works well with HDMI + Usb-B connection. Video signal, mouse and keyboard are ok. But on the other side, I have an Thinkpad T470S with Linux 5.16 and it's dock. Fist, I tried with usb-c(T470s) to usb-c(monitor) connection, xrandr couldn't detect the interface. With Displayport from dock, video signal works but usb-c for inputs don't.(I configured the KVM). Then I bought and tried with an adapter DisplayPort(dock) to usb-c(monitor DP Alt Mode), the result was the same as in the previous case. Y tried to activate typec_displayport kernel module unsuccessfully. Any idea how I can make it work? Thanks.