Rockpro64 USB-C DisplayPort 1.2 Compatability

I am attempting to use a USB-C to DisplayPort Cabel but the monitor does not appear. The Rockpro64 specifications say that the device supports DP 1.2 alt mode. My kernel version is 5.12.11-1-MANJARO.

Output inxi -Gazy:

[rock@rock ~]$ inxi -Gazy
  Device-1: display-subsystem driver: rockchip_drm v: N/A bus-ID: N/A 
  chip-ID: rockchip:display-subsystem class-ID: display-subsystem 
  Device-2: rk3399-dw-hdmi driver: dwhdmi_rockchip v: N/A bus-ID: N/A 
  chip-ID: rockchip:ff940000 class-ID: hdmi 
  Device-3: rk3399-mali driver: panfrost v: kernel bus-ID: N/A 
  chip-ID: rockchip:ff9a0000 class-ID: gpu 
  Display: x11 server: 1.20.11 compositor: marco v: 1.24.2 driver: 
  loaded: modesetting alternate: fbdev resolution: <missing: xdpyinfo> 
  Message: Unable to show advanced data. Required tool glxinfo missing. 

@David_W DP Altmode is very hit’n’miss on ARM, as the drivers for it is not properly implemented in mainline and the patches we do have are very “hacky”. An update to kernel 5.13.X could help though.

An update did not bring any improvement. I’ll be looking for a x64 board with DP.