External monitor no video input over HDMI

User Support
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1

I use a T480s with integrated graphics only.
This has worked before without problems, this is the first time im trying external monitor on 4.1 version. The display is fine I have tried on other setups and also tried with TV same thing happens no input signal.

Xrandr shows the monitor
Display settings shows the monitor I can change resolution and everything

Screen stays black it says no video input.
If however I try to set up the screens as mirrored in the display settings both the laptop screen and the external monitor will revert to a weird resolution 1650x1024 or something and then i will get a screen on the monitor full of artifacts.
ez

2

Can you try to set your setup options in dom0’s terminal using xrandr?
Something like that:

xrandr --output <laptop-monitor> --primary --mode 1920x1080 --output <external-monitor> --mode 1920x1080 --right-of <laptop-monitor>

Replace <laptop-monitor> and <external-monitor> with the name they have in xrandr output.

3

IMG_20231121_135640_962
IMG_20231121_135640_9621920×1440 189 KB

They are set up like this. Why is it 1920x1080+1920 ? This might be the issue ? what does +1920 mean?

4

The “+1920” you see refers to the current monitor position (to the right of your primary monitor).
I can’t see the selected mode for the other monitor, is it also on 1920x1080?

5

Yep, this is the laptop screen

IMG_20231121_142836_978
IMG_20231121_142836_9781920×1440 204 KB

6

What is the current state of the external monitor, is it still showing “no video input”?
Have you tried live-booting a Linux system like Ubuntu to see if your monitor setup works correctly?

7

Yeah its just black screen, if I try to replug the cable it will say no video input.
It has to be something with xcfe I think… it should be just plug and play

8

You said in your main post that it worked before. Was it on Qubes itself or on another distro? Was it recently?

9

Yeah I’ve been running qubes since like 3.2 with this exact same monitor, never had an issue just plugged it in and it worked. Also wherever I went I could just use hdmi never had an issue.

That being said I have not used hdmi since I reinstalled the os with the 4.1 version.

10

I’d try the same cable and monitor with another laptop/pc for the next step.