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PullJosh
Asked: 2018-05-09 14:04:59 +0800 CST

External monitor not detected on Ubuntu 18.04

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After upgrading to Ubuntu 18.04, my laptop has been unable to detect/use an external monitor attached via HDMI. Even when plugged in, the "detect displays" button within the default settings app doesn't do anything.

Here is the output from xrandr:

Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
eDP-1-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 194mm
   1920x1080     60.01*+  60.01    59.97    59.96    59.93  
   1680x1050     59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1600x900      59.99    59.94    59.95    59.82  
   1280x1024     60.02  
   1440x900      59.89  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1440x810      60.00    59.97  
   1368x768      59.88    59.85  
   1360x768      59.80    59.96  
   1280x800      59.99    59.97    59.81    59.91  
   1152x864      60.00  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   800x512       60.17  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98  
   576x432       60.06  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
DP-1-1 disconnected (normal left inverted right x axis y axis)
HDMI-1-1 disconnected (normal left inverted right x axis y axis)

My main concern is the final line: HDMI-1-1 disconnected. There is a monitor plugged in and ready for use, and nothing I do seems to cause it to be detected.

I have an nvidia graphics card, and before the update I was using proprietary drivers. When the external display problem first arose, my initial attempt was to switch back to the open source Xorg drivers. However, upon reboot, Ubuntu displayed my driver settings as using a "manually installed driver", and won't let me change it:

enter image description here

Any recommendations?

multiple-monitors xorg drivers nvidia hdmi

30 Answers

  1. I solved it by purging, then reinstalling the nvidia drivers

    sudo apt-get purge 'nvidia*'
sudo add-apt-repository ppa:graphics-drivers
sudo apt-get update

    Then using the Software & Updates tool's Additional Drivers tab and installing the latest nvidia drivers

    • 75

  2. Solved for me by updating to recommended Nvidia card drivers how-to.

    To install all recommended drivers:

    sudo ubuntu-drivers autoinstall
    • 38

  3. I solved the problem installing lightdm and set it as the default display manager.

    In the process, something changes because is starting to detect external displays again even if you go back to GDM3.

    You can follow the instructions here on how to make these changes:

    • sudo dpkg-reconfigure gdm
    • select the display manager (LightDM, MDM, KDM, Slim, GDM) you want to use by default and hit enter
    • restart your computer
    • 30

  4. Sweet Merciful Crap! There is a solution without installing lightdm!

    Update:

    It's apparently a better solution to run X11 as root. The one-line fix is to add this to this to /etc/X11/Xwrapper.config:

    needs_root_rights = yes

    It's a one line fix in /lib/systemd/system/gdm3.service

    Replace

    [Service]

    ExecStartPre=/usr/share/gdm/generate-config

    with

    [Service]

    ExecStartPre=/usr/bin/xinit /usr/share/gdm/generate-config

    Found Here:

    https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1716857

    All my external displays are now detected and working on gdm3

    My System:

    Ubuntu 18.04.3 LTS

    Lenovo T480

    Intel® Core™ i7-8650U CPU @ 1.90GHz × 8

    GeForce GTX 1070 Ti/PCIe/SSE2 via Razer Core X over Thunderbolt 3

    GNOME 3.28.2

    • 23

  5. My external monitor plugged into my Lenovo L380 HDMI stopped working on Ubuntu 18.04. I succeeded to fix this issue by opening the BIOS setup and changing the display priority option from the USB Type-C to the HDMI.

    • 5

  6. I attempted the solution that says to reconfigure to lightdm but that did not seem to work.

    I did some reading from the following website: https://devtalk.nvidia.com/default/topic/1035768/linux/ubuntu-18-04-can-t-see-second-monitor/ and I found that at least on the Lenovo Legion Y530 the solution is to change the NVIDIA prime profile from intel to nvidia and then restart the computer.

    You can switch the profiles by going to 'NVIDIA X Server' settings, going to the 'PRIME profiles' tab and then selecting 'NVIDIA (performance mode)'. After, restart the computer.

    You can also reconfigure the PRIME profiles tab by running the following command in the terminal. 

     sudo prime-select nvidia

    and then restarting your computer.

    • 5

  7. Try this (change resolution, if 1920x1080 is not your resolution):

        xrandr --addmode HDMI-1-1 1920x1080
    xrandr --output HDMI-1-1 --mode 1920x1080
    • 4

  8. I had similar problem, played with UEFI & Legacy boot mode, searched for hours but finally got it done by following ways: 1. goto Software & Updates 2. Additional Drivers 3. Changed the display driver from there. 4. restart

    enter image description here

    • 4

  9. People who are still struggling to setup your external monitor with Ubuntu 18.04. Just disable Secure Boot at the BIOS settings and give it a try. It worked for me. (ASUS ROG G531GV)

    • 4

  10. I had the same issue on an my Asus ROG laptop (running Ubuntu 19.04 / Windows 10 dual boot) after a BIOS update.

    First I had to disable secure boot in BIOS.

    Then I had to set options nvidia-drm modeset=0 in /lib/modprobe.d/nvidia-kms.conf and run sudo update-initramfs -u.

    • 4