XFCE, external display stopped displaying, only laptop default one works

Laptop has external monitor connected to it via HDMI, at first it worked to display on both same content.
But now somehow external display is black. So how to reset display settings or fix this please?

btw. i have not yet understood why the Display configuration window sometimes show mirror displays x mirror screens what is what and how to handle that.

Please post the output of xrandr

output is here.

but i made it working with messing with Display config. winfow things and suddenly it started working, i do not know how. Maybe helped to reconnect the cable too or reordering displays by mouse drag & drop left to right. Enabling mirror.
Thank you for your previous comment.

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I’m glad you got it working. I marked your post as the solution.

today is the second time when i came to a computer after a while and external display was not displaying, i had to reconnect the HDMI cable to the computer. Then within like 5 seconds after login it started displaying. Please what to do in order to discover cause of this next time this happen, or to setup some log or something?

I’m not sure. You may find something in jounalctl -bor in cat /var/log/Xorg.0.log.

Looking at your xrandr output, I can see both monitors are detected and active. You can see if they are active by the * symbol on the displayed resolution.

If this happens again, first check if the monitor is present and then you can activate it with xrandr. For example,

xrandr --ouptut eDP1 --auto --primary --output HDMI1 --auto --right-of eDP1

will set the default resolution for the external monitor and place it at the right of the laptop’s monitor. You can get more info with xrandr --help.

You can then put the command you pretend in a script so you don’t have to write it everytime.

If the external monitor effectively disappears from the xrandr output, then there’s a nother problem to look at.

After the HDMI reconnecting the image on external monitor appeared. Then i closed the laptop lid and after several seconds the image disappeared from ext. monitor (i do not know, maybe that was accidentally the 2 minute power saving (Screen blanking). Then after another reconnect (monitor was not reacting on mouse/keyb. - laptop screen yes) i checked the journalctl -r (reverse, show most recent items first). And i have not seen any entry related.
But /var/log/Xorg.0.log shown these lines:

[155071.696] (EE) event5  - Cypress  PS2toUSB KBM Bridge V2.02a Mouse: client bug: event processing lagging behind by 19ms, your system is too slow
[155071.838] (EE) event5  - Cypress  PS2toUSB KBM Bridge V2.02a Mouse: client bug: event processing lagging behind by 13ms, your system is too slow
[155377.698] (EE) event5  - Cypress  PS2toUSB KBM Bridge V2.02a Mouse: client bug: event processing lagging behind by 12ms, your system is too slow
[155510.730] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155510.744] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155510.748] (II) intel(0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (0, 0), rotation normal, reflection none
[155510.862] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155553.740] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155553.748] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155553.749] (II) intel(0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (0, 0), rotation normal, reflection none
[155553.865] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155643.971] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155643.974] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155643.979] (II) intel(0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (0, 0), rotation normal, reflection none
[155644.105] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155659.718] (II) config/udev: removing device Atmel Atmel maXTouch Digitizer
------->>>>> [155659.718] (II) event10 - Atmel Atmel maXTouch Digitizer: device removed**
[155659.740] (II) UnloadModule: "libinput"
[155695.822] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155695.825] (--) intel(0): HDMI max TMDS frequency 220000KHz
[155695.827] (II) intel(0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (0, 0), rotation normal, reflection none
[155695.959] (--) intel(0): HDMI max TMDS frequency 220000KHz

i guess the highlighted line is when the lid was closed…

previously i was also checking xrandr output as you have suggested @mbb when the monitor was not responding and this was the result.

I was also checking “journalctl -r” during the previous occurrence of the issue (ext. monitor does not wake up after computer being idle for longer amount of time) and extracted some lines that may be interesting. That xorg and journalctl output is here. That journalctl was full of “ss-qt5[1992028]: TCP connection timeout.” but that is not related issue possibly.

Try to attach a usb hand mouse and see if the problem persists.

I tried to attach different computer USB mouse than the one i was using and i have seen this to happen even with the new one. On Raspberry Pi computer with Raspbian is some kernel or such setting to keep computer emit video signal to HDMI even it does not detect the screen: https://raspberrypi.stackexchange.com/a/2171 . Is there any such setting in arch/Manjaro? Or from the logs i have shown is no apparent reason for this to happen?

I have no idea, but I don’t think so.

I don’t know every message’s meaning in the logs. What I see some apparent difficulty in keepong a mouse (apparently a touch mouse or a touch screen) attached with a workign driver. I also see the external monitor being set multiple times, but that’s maybe related to you swicting the cables or it going on and off.

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