How to let the Hyper-V / Virtual Machine Connection window use native resolution instead of incorrect high-DPI scaling?

Question

I installed Ubuntu 14.04 on a Hyper-V virtual machine hosted on Windows 8.1. It all runs on a Surface 3, so the high DPI scaling is enabled on Windows.

I also have a plain old full HD secondary display attached to the Surface.

Now, I managed to get my Ubuntu installation use a 1920x1080 resolution, but it does not look correct on my 1080p secondary display.

This how it works:

• If I drag the Hyper-V/Virtual Machine Connection window to the Surface high-res display, the picture is sharp but small, and one pixel in Ubuntu equals to one physical pixel on the Surface display.

• When I drag it to the 1080p secondary display the whole thing is scaled down so that the window sizes would rougly match that on the Surface. As a result the Ubuntu screen is blury and small.

This is the exact opposite of what should happen:

• On the Surface display, the Ubuntu screen should preferably be scaled up
• More importantly, on the secondary display, the Ubuntu screen should match the physical pixels and use all the real-estate when in full screen mode

Any ideas on what is going wrong here with the scaling, and how I could fix it?

Answer 1

You can try setting the compatibility flags directly in the registry which are at the following registry location:

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers

In that key, create a (string) entry as such:

• Name: C:\Windows\System32\vmconnect.exe
• Type: REG_SZ (String)
• Data: ~HIGHDPIAWARE