Not applicable

Dual DP - Optiplex 7040

Hi all,

We have a new Optiplex 7040 with dual display ports. However, only one of the DP's is working. I can plug in any of the two monitors into one of the display ports and get the display working, but not using the other port. Both monitors are set to use Auto-detection of input signal.

Within windows 10 both of the displays are detected, but only one of them will present. Not even the "identify" button will display a monitor number on the screen. I can move the mouse cursor out of the working screen and thereby see that it somehow is in use. If I switch ports of the monitors cables, the second monitor will show the secondary desktop.

BIOS is updated, video drivers are updated, chipset is updated.

Within BIOS there is no option to set Video to "Multiple monitors" as it can be on some models.

Any ideas?

0 Kudos
1 Reply
Community Manager
Community Manager

RE: Dual DP - Optiplex 7040


Video card DVI/HDMI out cannot up convert to Monitor DP/mDP in via a straight cable


Ensure that the display video in setting of the display matches the cable input used.
The default input setting is set to full size Display Port. If this is manually changed it must match the input being used or no display will result.

If the Mini-DisplayPort (mDP) connection on the display is used, then the input selection of the On-Screen Display (OSD) will need to be changed to mDP.

Confirm the DisplayPort (DP) configuration of the display.

If your system supports DP version 1.2, the monitor can display the resolution of 3840x2160 @ 60hz. The display Multi-Stream Transport (MST) should be set to "Off" which is default condition.
MST Off: (DP1.2 mode for single monitor setup) Default mode: 4k*2k 60Hz with MST function Disabled.
MST Primary: (DP1.2 mode for daisy chain setup) MST function enabled for primary monitor in Daisy Chain setup. Expected resolution is 4k*2k 30Hz with MST (DP out) enabled.
MST Secondary: (DP1.1 for daisy chain and single display setup) MST function disabled for secondary monitor in Daisy Chain setup Expected resolution is 4k*2k 30Hz with MST (DP out) disabled.
If computer supports DP version 1.1, monitor will not be able to achieve 3840x2160 @ 60hz. It will support lower 60 Hz resolutions such as 2560x1440 or 1920x1080.
Through the Monitor’s On-Screen Display menu (OSD), change the option from MST "OFF" to MST "Secondary" (You are changing the monitor’s setting from DP 1.2 to 1.1).
It may be necessary to restart the computer for monitor settings to activate.

NOTE: The D3100 Dell Docking Station-USB 3.0 does not support Multi-Stream Transport (MST) (Daisy-Chaining of DisplayPort Displays)

The monitor can now get the resolution of 3840x2160 @30hz. The current resolution can be verified on lower left side of monitor menu.

If your system only supports DP version 1.1, monitor may get No Video condition. With older video drivers, there is a chance of getting No Video when the monitor MST is set to "Off" or "Primary".

The following "Hot Keys" will change the MST settings to MST Secondary. You are basically changing the monitor’s Display Port modes from DP 1.2 to 1.1Press any key (excluding power button) to show the following dialogue box "There is no signal coming from your computer"
Press any key again and the "input source" menu will appear.
Press the green check mark (√) button for about 8 seconds and the following dialogue box will appear, "Set MST option to secondary"
Press the green check mark (√) again the DP mode will change from DP 1.2 to DP1.1
The monitor is now set to MST secondary and Resolution will be 3840x2160 @30hz.

* For DP, there are no drivers to support link training or hot plug detect

* You cannot turn off/on the display when the PC is in the BIOS mode or any DOS mode. This will result in no picture and you must reboot the PC

* Removing the DP cable or power cycling the monitor does not bring the display back. This is normal behavior and you must reboot the PC. This happens only on DP and does not affect DVI and VGA. This behavior is across the graphics industry. It applies to all graphic cards which affect all DP displays

* If you lose DP audio when awakening from sleep or screensaver, while the PC and monitor are on and you have picture, disconnect/reconnect the DP cable from the PC

I turned DisplayPort 1.2 on and get a black screen?

This means that either your video card or the driver is not DisplayPort 1.2 MST compliant.

* Press the monitor Input Source select button
* Highlight either DisplayPort or Mini DisplayPort
* Hold the green check down for 8 seconds
* Disable DisplayPort 1.2

Display Port
Display Port is a new digital standard for connecting monitors to computers and has the capability to provide a scalable digital display interface with optional audio and high-definition content protection (HDCP) capability. Display Ports usually resemble USB Ports with one side angled.
A Display Port cable should be used if Display Port connectors are available on both the computer and the monitor.



0 Kudos