Surface Dock not putting monitor to sleep

I have a Dell U2718Q (4K monitor) and encountered this issue. It was not a problem with my previous U2713H (1440p monitor, also connected over DisplayPort to the dock).

Symptoms: 

• When connected to the dock, with the Surface sleeping, the monitor was repeatedly going to sleep and then waking up only a few second later. 
• When connected to the surface, with the Surface sleeping, the monitor was sleeping nicely.

My resolution:

Switching Input Source -> Auto Select to "On" in the U2718Q's on-screen interface made the issue go away. The monitor was actually configured this way by default, but I turned Auto Select off to lock it onto DisplayPort (and stop it from scanning inputs every time it went to sleep). This is a compromise I am more than happy to make; the monitor now takes longer to go to sleep initially, but it sleeps well.

I am having the exact same issue on 34UC88W-B LG monitor.  I just ordered the adapter and cable.  WTH Microsoft you need to fix this, this is terrible!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks for the info.  Same issue here.  Using pure mDP to DP for my Samsung UE510.  Won't sleep with surface attached to dock.  Will sleep with surface detached.  Will try the cable/adapter combo.   

Ok, I am replying to my post about this because I have fixed my issue.

The way I fixed it was buying an ACTIVE mDP to HDMI adapter (one that supports 4K @ 60Hz) and using that with my monitor.  I have had no luck using the direct mDP to full DP cable.

Thanks for sharing, this solved my issue as well.  Monitor sleeps like a baby now.

For reference here are the adapter and cable I'm using:

Adapter: https://www.amazon.com/gp/product/B00PJ3LSIG/ref=oh\_aui\_detailpage\_o00\_s00?ie=UTF8&psc=1

HDMI Cable: https://www.amazon.com/gp/product/B014I8SIJY/ref=oh\_aui\_detailpage\_o00\_s00?ie=UTF8&psc=1 

Ok, I am replying to my post about this because I have fixed my issue.

The way I fixed it was buying an ACTIVE mDP to HDMI adapter (one that supports 4K @ 60Hz) and using that with my monitor.  I have had no luck using the direct mDP to full DP cable.

Thanks for sharing, this solved my issue as well.  Monitor sleeps like a baby now.

For reference here are the adapter and cable I'm using:

Adapter: https://www.amazon.com/gp/product/B00PJ3LSIG/ref=oh\_aui\_detailpage\_o00\_s00?ie=UTF8&psc=1

HDMI Cable: https://www.amazon.com/gp/product/B014I8SIJY/ref=oh\_aui\_detailpage\_o00\_s00?ie=UTF8&psc=1 

Wow I can't believe I finally found people that were having the same issue as me!! I checked so many forums without success.

Fortunately my monitor also has HDMI, so I will order this active adapter asap! I had been plugging the second monitor directly into the SP4 so that I didn't have to manually turn off the monitor for over a year now and it is starting to wear out the connector. It flickers on and off if the cable moves now, so I was frantically looking again for a solution.

This is exciting, I hope it works. I believe last year when I called Microsoft about this they made sure I was using DP input! Geez! I can't believe Microsoft is still clueless. I am glad I didn't waste my time going to the Microsoft store. Now I just need to figure out whether to keep the 32" 4k or the 34" ultrawide since I just bought different monitor to see if it would work properly. (it didn't)

Thanks for posting this!! If it works I will post an update!