Dell WD15 Business Dock - USB2.0 Audio 2 "Stream 2" disabled
I have a Dell Precision Mobile Workstation for work and my 2017 13" MBP w/Touch Bar for personal use, and I have nearly identical setups at home and at the office. The Dell TB16 dock at the office doesn't work with the Mac, however I just got a Dell WD15 dock for home because it charges (and works with) my work laptop and I thought it would also work with my Mac - but it has some issues.
When I first plugged it in, the MDP worked at 1440p/60, the native resolution of the display, but the dock's rear audio jack didn't work. I updated the firmware with the Dell, and after that the MDP would only output 1080, however the HDMI outputs 1440p/60, so that's how I'm using it. It worked fine with the Dell before and after the update.
I now have only one lingering problem with the dock - the audio. In the utility "Audio MIDI Setup", Realtek USB2.0 Audio 1 has two input streams and Audio 2 has four (2x stereo) output streams; Stream 1 is the front headset jack stereo pair and Stream 2 is the rear line output jack stereo pair. Audio 1 must be the headset mic input from the front jack.
As you can see in the screenshot, Stream 2 is disabled. Why? Can I enable it somehow? I'd like to be able to use the rear jack. It works fine on the Dell, and the whole point is to have a single dock that charges and works with both devices.
MacBook Pro (13-inch, 2017, 4 TBT3), macOS High Sierra (10.13.2)
