I am using a ThinkPad X1 with an Intel HD Graphics 520 card and have installed Ubuntu 16.04 (and upgraded linux kernel to 4.4.21). I installed ubuntu-gnome-desktop, then configured gdm as the graphics manager instead of lightdm.

Additionally, I followed the steps described here to download the Intel installer for Ubuntu 16.04, from which I updated the driver and rebooted. This did not change anything with the inability to use the second display and did not cause xrandr to begin detecting the HDMI port.

I am unable to get the system to detect a second display via any connections. I've tried through the OneLink dock via DislayPort cables. I've tried a direct mini DisplayPort to a DisplayPort on the monitor. And I've tried with an HDMI cable between the two. In all cases, I can't detect the external monitor, and xrandr only lists a single screen, 0, corresponding to the LCD screen on the laptop itself.

If I go into BIOS and I change the boot display setting so that HDMI is the boot display, then the HDMI connection does work, and the system boots and displays on the external monitor. But if I unplug the monitor, the built-in LCD screen on the laptop does not turn on, and remains black. And I still cannot detect any secondary display, not even the built-in screen.

How can I support both monitors (built-in screen and external display)? The system does not detect additional displays at all.

Previously I had tried poking around with nvidia settings and drivers, but this did not help (and let to frustrations with the nvidia driver login loop problem). It's an Intel graphics card, as mentioned earlier.

Basically, the output of xrandr --prop worries me the most, since it does not detect any other displays apart from whatever is chosen as the boot display. It should show that there is a dock DisplayPort connection, a mini DisplayPort connection, and an HDMI connection all on this machine, all disconnected (or something). But it doesn't show them at all -- leading me to believe the graphics card itself is configured in some way that only permits a single display.


This question is fairly old, but hopefully this answer helps still.

The best course is to upgrade your display drivers. Intel has upgraded their graphics updater to work with Ubuntu 16.10, however it might not work yet with Ubuntu 17.04, even with the suggested changes in the link above (my blog).

Once the display drivers are up to date, you can install the latest DisplayLink drivers. I've verified that they work with Ubuntu 17.04, but they will need a slight modification to an xorg configuration to make them responsive. You can see my results here: https://github.com/DisplayLink/evdi/issues/85

Next make sure that you have the correct cables from the DisplayLink to your monitor. You cannot use an HDMI to DP connector unless it's powered, or so I read (some other cables may support video but I haven't tried them), so the easiest method is to use a DVI to HDMI, DVI to DVI, DVI or HDMI to VGA, or HDMI to DVI. You can also use a DisplayPort (DP) to DP cable.

Make sure that your cables are securely installed. I made the mistake of having a loose connection so the monitor showed in the Displays tool but wouldn't turn on and wouldn't display video on the monitor.

For reference, my machine is a Yoga 900 with an Intel HD 520 as well. It should be a close match to OP's ThinkPad X1 in terms of hardware.


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