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Federico Magliani
Asked: 2018-09-27 00:29:30 +0800 CST

HDMI port not detected on Ubuntu 18.04

  • 772

the HDMI port of my lenovo ideapad 500s with Ubuntu 18.04 LTS is not working.

I also executed the xrandr command, but only the primary monitor is detected.

How can I solve my problem?

How can I check that HDMI is not broken?

Thanks in advance.

multiple-monitors hdmi 18.04

14 Answers

  1. The same thing happened to me but I was able to solve it. My solution was:

    1. Turn off the PC.
    2. Disconnect the HDMI cable.
    3. Turn on the PC (without HDMI).
    4. Log in.
    5. Reconnect the HDMI cable.
    • 46
  2. Best Answer

    How can I solve my problem?

    What worked for me (Lenovo thinkpad x1 Carbon, Ubuntu 18.04 LTS), is either switching the display manager back and forth between gdm3 and lightdm

    sudo dpkg-reconfigure gdm3

    and/or reinstalling lightdm and reconfiguring it again instead of using gdm3

    sudo apt-get install --reinstall lightdm ubuntu-desktop
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  3. In case you using Nvidia graphics card the nvidia-driver could be a problem.

    In my case, I've been using my Lenovo Y530(GTX 1050 ti) with Ubuntu 18.04 with nvidia-driver 415.xx which hasn't been supporting the secondary monitor through HDMI. I've tried in many ways with no luck. I finally upgraded the driver to 418.39 and the secondary monitor began to work! :)

    But be careful in case you decided to go and install the driver but are not used to. There are some scenarios which can harm your system which would eventually lead you to format the system.

    • 6

  4. What happened to me was that i got a kernel driver dependency not updated/installed.

    I discovered it by running sudo ubuntu-drivers autoinstall on my terminal and recieving the following error message:

    Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 nvidia-driver-470 : Depends: nvidia-kernel-source-470 (= 470.86-0ubuntu0.20.04.1) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

    Simply installing the missing dependency (in my case nvidia-kernel-source-470) for my driver (nvidia-driver-470) and running the autoinstall again worked. So the steps were basically this:

    • Run sudo apt install nvidia-kernel-source-470
    • Run sudo ubuntu-drivers autoinstall again. Obs: Make sure you are using the correct driver, in my case nvidia-driver-470
    • Reboot and you are ready to go!

    My specs:

    • SO: Ubuntu 20.04
    • Computer: Lenovo Ideapad Gaming 3i
    • Graphics card: Geforce GTX 1650

    Hope it helped!

    • 4

  5. In my case it was broken VGA -> HDMI adapter (finally it just burned out).

    I suggest this steps to troubleshoot your problem.

    • try to reboot
      • disconnect cable
      • sudo reboot
      • after system start and log on - connect cable again
    • Check another HDMI cable
    • Check another Display/TV with current HDMI cable and different HDMI cable
    • If you use HDMI->VGA adapter - check it
    • lshw -C video - check that you have HDMI there, if not - try to check:
      • your laptop HDMI connector
      • different cables
    • check xrandr --listmonitors - that you have another display there
    • check which display manager you use
      • sudo systemctl status display-manager
    • try different display managers (gdm3 or lightdm)
      • sudo dpkg-reconfigure gdm3
    • 3

  6. Sharing my experience here, maybe it will help others.

    My HDMI doesn't work after a BIOS update. I shut down the computer, and then manually disabled "Secure Boot" and "Fast Boot". I've disabled it before but it seems the BIOS update reset some settings.

    Monitor works again after this.

    • 3

  7. In my case, the NVidia drivers where the trouble. When using the Noveau software the problem was solved! Thanks

    • 2

  8. Sharing my experience:

    1. Upgrade 20.04 to 20.10 -> not fixed
    2. Reconfigured gdm3 -> not fixed
    3. Switch from gdm3 to lightdm and back to gdm3 -> not fixed
    4. Disconnect the cable, reboot, login, reconnect -> fixed ( @littleguga solution )
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  9. Form my situation (Ubuntu 20.04 Dell-5500) my problem was about UEFI Secure Boot.

    Did these and worked for me:

    1- Open a terminal (Ctrl + Alt + T), and execute sudo mokutil --disable-validation.

    2- Enter a temporary password between 8 to 16 digits. (For example, 12345678, we will use this password later

    3- Enter the same password again to confirm.

    4- Reboot the system and press any key when you see the blue screen (MOK management

    5- Select Change Secure Boot state

    6- Enter the password you had selected in Step 2 and press Enter.

    7- Select Yes to disable Secure Boot in shim-signed.

    8- Press Enter key to finish the whole procedure.

    Lastly to re-enable Secure Boot validation in shim, simply run sudo mokutil --enable-validation.

    Solution link here : solution

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  10. Same problem was on my Ubuntu 18.04.5 on Dell G3 3790 laptop. Fixed by changing "Ubuntu Wayland" to "Ubuntu" when pressing a small cogwheel on login screen.

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