I just bought a Mobile WS 7680 running Ubuntu, but bought a WD22TB4 dock. I kept getting a warning that it was under powered. It would have been nice if the store had told me! I now own a WD19DCS Performance dock. It has the exact same port configuration as the  WD22 so I just plugged in everything the same way. I got video, but no USB. All my dock-connected peripherals were not recognized.

My configuration is as follows: WD22 dock, Dell 27in monitor plugged into dock, Dell A215 speakers (very ancient!) plugged into monitor, Logitech camera plugged into monitor, Dell wireless keyboard and mouse plugged into dock (mini dongle).

I copied this config onto the WD19. I had video, but nothing else. I had to use my laptop keyboard and mousepad to do anything. Moving the dongle to the laptop worked for my keyboard and mouse. I messed with the BIOS settings and got the USB to work but now had lost video!

I tried the updating everything, but that didn't help. I found a bug in the BIOS but that is a different issue and is unrelated.

I finally gave up tweaking and reset everything to the BIOS default. Everything (audio, video, and USB) is working now.

If you are having issues, try resetting the BIOS to default.

Good luck!