External Monitors Not Working After Upgrade to 23.10

After upgrading from 23.04 to 23.10, I encountered an issue with my laptop and dock setup, where the two external monitors connected to the dock stopped functioning properly.

Issue Details:

  1. The monitors are detected in Settings > Monitors.
  2. I can toggle them on and off and rearrange their positions next to my laptop monitor in the settings.
  3. However, there is no actual desktop being rendered on the external monitors.
  4. Boot messages are still visible on the external monitors when the desktop is shown.
  5. Pressing Ctrl + Alt + F3 displays the tty login on the external screens, but the desktop on the laptop screen freezes.

Steps to Reproduce:

  1. Upgrade from version 23.04 to 23.10.
  2. Connect laptop to dock with two external monitors.

Expected Behavior:
External monitors should function correctly after the upgrade, displaying the desktop and allowing normal use.

Additional Information:

  • Laptop model: lenovo T430
  • 23.04 was freshly installed on this laptop
  • In 23.04, the LUKS passphrase prompt showed on all screens, but with the upgrade to 23.10, it only displays on the laptop screen.
  • Attempted to start the desktop using the following methods:
    • Normal desktop login.
    • Xorg desktop.
    • startx command from the tty.

Please let me know if you need any further information or if there are specific troubleshooting steps I should follow.

Asked By: Ruben

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Source

Please try to revert to the previous kernel version (as by your description it worked with Ubuntu 23.04) and see if the error persists. Kernel updates are known to cause issues with the above described.
To do this, follow these steps for testing purposes:

  1. The different kernel versions can be seen in the GRUB boot menu. Take a picture of this instruction here and shutdown your machine.
  2. While booting, hold the SHIFT key
  3. With your arrow keys (up and down) pick a kernel starting with 6.2
  4. Hit enter and boot. This option is only temporary, don’t worry.
  5. Test your screens
  6. Should this solve the issue, you need to set that kernel as the default boot kernel by following above steps again. Marking the kernel one more time with the arrow keys and then pressing the "d" key (for "default") on your keyboard. The arrow marking the default boot kernel will then move to the line you marked.
  7. Press Enter again and the default boot kernel has been changed.

This setting can be changed anytime following the above steps.
I hope this solves your issue as it did for me.

Answered By: Lorberta

You will get more and better answers if you provide more helpful information in your question, as much as you can.

  • What kind of GPU?
  • What graphics driver are you using?
  • What are these 2 screens? How are they connected?

I have never seen a Thinkpad T430, but I have two T420s. I know that for the T420 model, which CPU your laptop has is highly relevant to this: the Core i5 T420 has no discrete GPU and uses only Intel HD3000 graphics. The Core i7 T420 has 2 GPUs, both Intel integrated and a separate nVidia Quadro NVS 4200M, with Optimus switching.

So which model could matter a lot — but you didn’t specify.

Answered By: Liam Proven