Win 10 - inconsistent detection of external screens
 

Hello.

In our company we've recently completed a major fitout of a new office tower comprising of several thousand hoteling desks fitted with new Lenovo Ultra Docks (1x HDMI and 1x DisplayPort) and two external monitors (Lenovo ThinkVision T22i-10 panels).

Each desk has an identical equipment / cabling setup.

We've been receiving complaints from staff with new Windows 10 1703 (Creators Update) laptops running the DisplayLink 8.4 M2 client that the machine does not always correctly detect and setup the external displays when they 'sit down and plug in' at a new desk that they have not visited before.

We've run some tests and have verified these complaints.

In these tests our engineer randomly visited a dozen of the new desks, attached a Windows 10 laptop to the USB Dock, and booted up.

For roughly half of the desks visited the laptop detected the right screen (DisplayPort) and configured it automatically as an EXTENDED display. The left screen (HDMI) however did not appear to be detected, and hence did not receive a signal. I've appended a photo to this message to demonstrate the issue (refer Desk Example 1 attachment).

For the other desks visited, both external displays were automatically detected after the laptop booted up. The left display (HDMI) was automatically configured as a DUPLICATE of the laptop display, and the second screen (DisplayPort) was automatically configured as an EXTENDED display.

The same Win10 1703 laptop was used for each test, and as mentioned earlier, each desk has identical equipment / cabling setup.

Is there any reason for the differing display detection/setup behaviour ?

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Attachment 3489

Hi

Thanks for describing your issue. The reason this occurs is due to the way Windows remembers display layouts. The display layouts are stored by the OS based on the montior serial numbers and the group of monitors connected. This means that if you connect to a new hot desk, then the monitor serial numbers will be different, so Windows will not have a stored layout to apply.

By default Windows will mirror to new displays on a laptop, and extend to displays on a desktop computer. The display settings are then stored in Windows in the registry under:

HKEY_LOCAL_MACHINE\Systems\CurrentControlSet\Contr ol\GraphicsDrivers\Configuration
HKEY_LOCAL_MACHINE\Systems\CurrentControlSet\Contr ol\GraphicsDrivers\Connectivity**

Graphics drivers are explicitly prohibited from changing the default Windows display behaviour, so it maintains a constant experience, but we understand this is not good for hot desk use. A work around could be to use Actual Multiple Monitors, which can save and restore display layouts:

http://www.displaylink.com/downloads...-monitor-tools

Wim

Confirmation of incorrect screen detection behaviour
 

Thanks for the reply, Wim.

In particular I note your statement “By default Windows will mirror to new displays on a laptop” . In examining the two photographs the expected behaviour does not appear to be occurring.

In Desk Example 1 the default behaviour of the Win10 1703 laptop upon connecting to the dock was to set external display 2 (Displayport) to Extended, with external display 1 (HDMI) set to Disabled.

In Desk Example 2 the default behaviour of the Win10 1703 laptop upon connecting to the dock was to set external display 2 (Displayport) to Extended, with external display 1 (HDMI) set to Duplicate.

So this seems to confirm the solution is not working as expected.

have the same issue, still looking for an auto extend solution