External HDMI monitor no signal after the screen is turned off and on

Do you have any of the settings set in advanced for the external display?

Yes just the following default setting so I can turn off the monitor on the laptop itself and use the external monitor as primary. I have tried both with and without profiles, it does the same thing. So I’m thinking there is something else at play here that I am missing.

Do you have the laptop monitor set as primary display?

Edit: I’m just trying to understand how you turn off the primary display and then set to use the external?
Did you try setting the laptop as primary?

Neither of them are set as a primary display. I tried setting the external monitor as primary monitor as well, then turned it off, and on to try. It still gives a No Signal after it comes back on.

Did you try setting the laptop screen as primary?

I can’t set the laptop display to primary when it is disabled.

What i mean is normally you would have the laptop working and set as primary on the laptop display. Then you would hook up an external monitor and set it up to either be mirrored or not and you can use xrandr to set display settings and resolution if it’s different.

Edit: https://docs.xfce.org/xfce/xfce4-settings/display

Could be both. HDMI can be a bit finicky, and Xfce might not know how to handle it.

Sometimes it comes down to how the DE handles a monitor disconnection. HDMI-connected displays can disconnect completely when they power off, which means the PC will remove the output from the display configuration. Then, when the output powers on, the DE isn’t configured to use it.

Pulling the cable and re-inserting forces an electronics-level reset, which is why the laptop detects it again.

Yes I followed that page to setup this external monitor. At this point I’m thinking its the monitor that’s giving me these issues. Even if it works fine in windoze.

This, is a very good explanation on what I am experiencing right now. It doesn’t look like turning on the monitor sends a electronics-level reset to the laptop thus giving a No Signal message when its powered back on. My laptop also has DisplayPort output but I don’t seem to have a cable to connect it from the laptop to the monitor. This might be something else to try.

It might be worth trying a GNOME live image to see if that handles the disconnection. If it does, it’s Xfce. If not, it’s the monitor.

Like @jonathon say’s it’s probably the HDMI port because when you turn off the monitor it’s not detecting a signal so it shuts down because the detection comes from the laptop not the monitor. So turning the monitor back on it doesn’t sense a signal because it’s not looking for it. :thinking:

Edit: I think maybe some monitors keep power on to that HDMI port so this doesn’t happen?

I will try the DisplayPort Connector. I have ordered a cable. I will update here when I get to test it tomorrow. HDMI seems wonky here.

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That’s a good idea. It may be different. :thinking:

One other thing on the monitor settings check that it is proper selection for the port it’s using. You check that on the monitor in settings just so it isn’t auto searching to connect if it has multiple inputs.

Update: It looks more and more like the fault of the monitor. I hooked it up to another monitor I own that is 2K in resolution and I turned off the power on that monitor and turned it back on and it worked just fine. Now I know there is definitely something up with the monitor. HDMI port is out, and the jury is still out if the DisplayPort on the monitor does the same thing.

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One advantage of Display Port is that it supports both AMD Free-Sync and Nvidia G-Sync. Another advantage is Display Port supports multiple monitors from one Display Port connection. Keep in mind HDMI cable specs 1.4, 2.0 & 2.1 as it matters depending on what you are doing with respect to Hz, Resolution and also Audio. Same with Display Port cables. Usually you want to get a cable that is certified as such. Specs also 1.2, 1.3, 1.4, & 2.0 on Display Port.

Edit: These are just some examples which you may already be aware of.

Update: I got a DisplayPort cable and it works great, turning off the power to the monitor doesn’t give a No Signal when its powered back on. I got a DP 1.4 cable, even though I suspect the port on the laptop is 1.2. The HDMI port on the monitor is busted, but hey at least the DP works.

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I just got a 34" ultrawide. The included HDMI cable doesn’t let it run at full resolution or at its maximum refresh rate. I bought a high-quality DP cable (based on manufacturers listed on VESA’s certified DP cable list) and it works perfectly.

This is an annoying issue with modern displays - HDMI and DP have different implementations and those can have different quality of implementation too. GPUs can say they have support for a particular implementation level, but then the port they have doesn’t. Even the cables can’t be trusted…

Gone are the days of interchangeable VGA and DVI cables… :weary:

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This is exactly the issue i mentioned to @Anticupidon about cables and running higher resolution and refresh rates. Not all hardware is the same and neither is quality of it or cables when it comes to specs. Inferior quality that doesn’t meet the specs is a recipe for failure.

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