Laptop screen do not turn back on after disconnecting from HDMI source

Hello, everybody.

I have a Samsung laptop (model NP900-5XT) and I’m using Fedora 38. So, my thing is that I frequently use my laptop connected to a TV using a HDMI connection with the laptop screen set to off. If I remove the cable and the TV is on, everything works as expected, i.e., the laptop screen turns on. But, if I take the cable out and the TV is off, the laptop screen remains turned off. In this case, I have to reconnect the cable, turn on the TV and, then, disconnect the cable once more. It is a little bit annoying, but I don’t mind the trouble. But, on a rainy and sad day, the power went down, the laptop was connected to the TV, wich turned off and, as a result, I couldn’t get the laptop screen to turn on again. I had to reboot the laptop, which worked, but I lost some work that I was doing at the time.

Is there anything that I can do to solve this issue? I think that the expected behaviour would be that when the TV turns off, the laptop screen turns on, as it happens when the cable is disconnect.


This should not happen if both screens are powered on at the same time, but seems expected if the laptop screen is disabled when the external screen is in use. Nothing would trigger the power up of the laptop screen in the situation you describe.

I think I understand what you’re saying, but the thing is that the OS seems to believe that, after a HDMI cable disconnection from a powered down TV, it is still connected to a external source. I mean, it is not automatically detecting the disconnection and then powering up the laptop screen, as per default.

The same goes if I’m using a dual monitor setup. If I power off one of the monitors, the OS keep showing me that there are two monitors connected and the disconnection of the cable changes nothing.

Of course not. The display in use is powered down so the system sees no active cable connection. Disconnecting the cable in that condition makes no change in what the system sees. For the system to see a disconnected cable the cable connection must be active – i.e. the monitor has to have power.
It can be in standby and the system should see when it is disconnected, but not when it is powered off

I understand, and this behavior is perfectly reasonable on a desktop since monitors have a button that allows you to turn them back on. However, on a laptop, there is no similar alternative. In other words, every time the system detects that the external output has been disconnected, it must automatically turn on the laptop screen again simply because there is no other way to do it.

Maybe the solution is as simple as allowing the user to configure the behavior of the laptop’s power button to turn on or off the laptop screen.

I have never turned off my laptop screen when using an external monitor so have not seen this behavior. Have no clue on how to debug further.

I always have both screens on and only mirror the output.