Laptop's built-in display not being detected after accidentally disabling it on Ubuntu

maxxxpool · June 7, 2023

Hello everyone,

The issue itself it not lengthy but I'll try to explain it in detail (with images and everything I've tried) so maybe you can identify the root problem more easily.

System Configuration:

I'm using an dual monitor setup where I have a external Dell monitor connected through HDMI to my Dell Latitude E5470.

I recently installed ubuntu 22.04.2 LTS alongside windows 11 (using dual boot) and am using it for development purposes.

What caused the issue?

A few days back, while messing with display settings on ubuntu i accidentally disabled the built in laptop display using the button on top right of display settings.

At the moment I thought I would just be able to turn it back on whenever so I didn't care much since I was mainly using the external display anyway.

But then sometime later, an ubuntu firmware update happened. And after that when I tried to enable the built in display from the display settings from the external display, it just wasn't there. The display settings showed up like there was only one display attached (See the image below)

One thing to note about this image is that, the system does realize that this is second monitor, indicated by the number 2 on the top left corner, it just doesn't detect the built in display for some reason.

Things I've tried to resolve it but failed:

1. On ubuntu, I disconnected the HDMI cable, since doing so normally auto switches to the builtin display, it did switch instantly but the laptop kept going to sleep (a.k.a suspended in ubuntu) just after a few seconds and I'd have to manually press the power button to wake it up and login again.

2. I tried opening display setting within the few seconds period I would get on built in display but that would freeze ubuntu and immediately go to sleep again.

3. I tried opening the display settings on external display and then unplugging the cable, so the built in display would be forced to display the display settings but the display settings page would just show one Night Light option (see image below)

4. I thought the issue could just be ubuntu related, so i restarted the system to boot into windows, and disconnected the HDMI cable so that it show everything on the built in screen. And everything appeared normal till windows loading screen, but after that the screen went blank, even though I could hear the windows startup sound. I then plugged the hdmi cable back and the lock screen appeared on external display. So i opened the display settings on windows on external display, but it also showed the settings as if there was just one monitor attached. (See the image below)

I can't check what the display settings look like for built in display on windows because as soon as I unplug the HDMI cable on windows, instead of showing everything on the laptop's built in screen, it just continues to display a blank laptop screen.

Few other technical things I've tried:

1. Tried to reset display settings on ubuntu using command line -- didn't work.

2. Tried reinstalling display drivers on windows -- didn't work.

3. Even tried reinstalling ubuntu but that didn't solve the problem either. And one particular thing to note about the re-installation was that even during the ubuntu installation from my usb stick, if i had the hdmi cable unplugged the built in display would keep going to sleep after every few seconds and i'd have to either constantly manually wake it up by pressing the power button of just attach the external display in which case it would switch to it and won't cause any issues.

4. Thought the issue must be bios related at this point since it is OS-independent, so reset the whole BIOS, but that didn't work either.

If anyone can help me revive my laptop screen, I'd be super grateful since my laptop is just 'windows mini' (derived from mac mini) at this point.

# EDIT 1: Please note that, I CAN work with BIOS on my builtin laptop screen as long as I want and that doesn't cause any issues. In bios settings, everything seems normal with the built in laptop screen.

Edited June 7, 2023 by maxxxpool
Additional Information that might be helpful.

maxxxpool · July 3, 2023

Just for any future people who might run into similar issue, here's the solution I've found that worked after months of looking for a solution. And it also aptly describes why the laptop runs into this issue in the first place (unlike my naive assumptions and futile attempts)

https://askubuntu.com/a/1413208/1450033