No audio over Surface Dock's display port

Question

Greeting community, I have the following issue:

No audio from the display port connection of my SurfaceDock.

Monitor: Asus MX34V with built-in speakers.

Cable: generic miniDP to DP

Laptop: original SurfaceBook i7 with dedicated GPU keyboard

Under playback devices, the item is properly displayed & enabled (Asus MX34V | Intel Display Audio). Trying the 'test' fails, and produces no sound. Other media playback also stays silent (e.g. VLC, Groove). This is what I've tested:

Are drivers / firmware out of date? No.

-Windows update claims SurfaceBook is up to date

-Surface Dock Updater (v2.12.136.0) reports firmware as being up to date

-Windows event viewer shows dock firmware was correctly updated, including DP:

 Installed DP firmware version: 049E3D71

 New DP firmware version: 049E3D71

Is the cable faulty? Is the monitor faulty? No.

Connecting the SurfaceBook directly to the monitor produces audio (ergo laptop, cable, & monitor work as intended).

Is the SurfaceBook not outputting audio to the dock? No.

Connecting headphones to the 3.5mm jack on the SurfaceDock, itself connected to the SurfaceBook, produces audio (ergo the dock is getting audio from the laptop).

Is the entire display port output faulty? No.

Connecting the monitor to the SurfaceDock, itself connected to the SurfaceBook, produces video but no audio (ergo the dock is not outputting correctly audio over display port).

It seems to me the dock has issues forwarding the audio over the display port connection. I've seen this issue appear in the forums a couple times, and I've tried their fixes, but I can't seem to get the audio to work. I've:

-rebooted the laptop, the dock, both

-unplugged waited and replugged

-ran the SurfaceDiagnosticToolkit

But so far, no luck.

Is there anything else I should try? Is my dock defective? Did the current firmware re-break audio output over display port (seems it did last year at some point before another update un-broke it...)?

Answer 1

Hi,

Thank you for providing us information regarding your concern and the things that you have done so far to resolve the issue. Can you confirm the following information so we will know where to start troubleshooting the issue:

• Have you tried using a different mini DisplayPort to DisplayPort cable or as suggested on this link?
• Have you also tried connecting your external monitor to your Surface Book using a different Surface Dock?
• Was there any chance in the past that the audio was working with the current set up? If yes, when did the issue start?

Regards.

Answer 2

Hi Erwin,

The link you provided suggested disabling DP1.2 in an attempt to, I presume, force using DP1.1 mode; however I was already using DP1.1 mode. So I switched my monitor to DP1.2, and now the audio is working... even though it is the opposite of what the troubleshooter says... Thanks for the tip.

For the record, in my setup, I get audio using DP1.2, but not using DP1.1, using an Asus MX34V display.