I have graphics card with 3 Displayport and 1 HDMI ports. The system responds correctly when I turn the power off/on button to the monitors connected to the Displayports. However, the HDMI monitor is still “seen” after pressing the power off button. See the number 3 monitor in the screenshot below. It shouldn’t be there.
The system somehow recognizes that the monitor is being powered off/on, because the multi-display settings change when changing the state of this monitor. But I can’t turn it off-off unless I unplug the power chord – not very convenient.
This is problematic because the mouse pointer can jump to that monitor 3 from 1, and sometimes new windows will open in that display, forcing me to turn on the monitor to move them to the active ones (maybe there is another way to pull these windows that I have missed?).
At the beginning the GDM login would render in that turned off monitor as well, but I found a workaround here to render it in the primary display only (1 in my case).
Relevant System Information:
Wayland
NVIDIA GeForce GTX 980
Linux 6.11.0-1007-lowlatency
Screenshots or Error Messages:
What I’ve Tried:
Switch HDMI / Displayport connections to see whether the problem came from the specific monitor or the connection, and the culprit seems to be the HDMI connection.
PS: I have searched online but with these keywords I get plenty of results about HDMI monitors not detected. Funny that I want mine to be undetected when powered off.
@hifron thank you for your suggestion. I checked the UEFI and… I didn’t find any obvious option related to power management affecting monitor ports. Any hints about what should I look for? I have searched online, to no avail.
Also, I wonder what setup in the BIOS would make Displayport to behave one way and HDMI to behave a different way, but I really have no idea what I’m talking about.
After further testing… maybe this is an HDMI / StandBy limitation?
We can remove Nvidia from the equation because the same problem happens if I plug the HDMI cable to the Intel graphics card port.
I tried on Windows (dual boot) and the same problem happens there too.
I tried different combinations of monitors and Displayport / HDMI. I believe the monitor model doesn’t play any role. It was always the monitor on HDMI the one that had the problem.
I’ve found a workaround, which is to use the HDMI cable for my primary monitor, which I use always when my PC is on. And all the secondary monitors are on Displayports and behaving as expected. It was counterintuitive to use the “old” HDMI with my primary monitor and “spend” a Displayport port with a secondary monitor that I don’t use most of the times, but at least I don’t get ghost displays this way.
Hello,
I don’t fully understand your problem, so forgive me if this is a useless reply, but your post reminds me a problem I had some years ago with the monitor.
My problem was due to the monitor’s “Auto” selection of the input source. In Kubuntu my monitor wasn’t able to go in standby when the input source was set to “Auto”. Everything worked fine if I force the monitor in “HDMI” source or “DisplayPort” source.
If your monitor has this kind of “auto” mode which automatically finds the input source you can try to disable it, forcing the monitor to the input source you need (HDMI in your case).
Thank you for your comments! But the problem is still there.
I’m on a PC running latest Ubuntu and Wayland. I have also tried combinations of primary & secondary vs HDMI / Displayport. The problem always tracks the HDMI connection.
I had changed the source to Manual already, to remove the “Auto” factor from the equation. And everything works fine when it comes to boot the PC and recognize the monitors. The problem is that if power off the HDMI monitor, it still appears as on in my system, and both the mouse pointer and app windows might end up in that ghost desktop that I can only reach by turning the HDMI monitor on again.
