Using xrandr to create a virtual display (Linux) #42

crisszkutnik · 2021-01-25T01:55:05Z

Creating a virtual display with xrandr that can be broadcasted as an extra monitor is fairly easy on Linux. I think that this method should be implemented as a guide as it is a viable method for Linux users without the need of extra drivers or a dummy plug. To achieve this I did the following:

First, run the following command:

xrandr

Command output

    DisplayPort-0 disconnected (normal left inverted right x axis y axis)
            DisplayPort-1 disconnected (normal left inverted right x axis y axis)
            DisplayPort-2 disconnected (normal left inverted right x axis y axis)
    HDMI-A-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
             1920x1080     60.00*+  71.91    50.00    59.94  
             1680x1050     59.88  
             1600x900      60.00  
             1280x1024     60.02  
             1440x900      59.90  
             1280x800      59.91  
             1280x720      60.00    50.00    59.94  
             1024x768      70.07    60.00  
             800x600       72.19    60.32    56.25  
             720x576       50.00  
             720x480       60.00    59.94  
             640x480       72.81    66.67    60.00    59.94  
             720x400       70.08  
    DVI-D-0 disconnected (normal left inverted right x axis y axis)
             1920x1080     60.00  
    DP-1-4 disconnected (normal left inverted right x axis y axis)
    HDMI-1-2 disconnected (normal left inverted right x axis y axis)
    DP-1-5 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 531mm x 299mm
             1920x1080     60.00*+
             1680x1050     59.88  
             1280x1024     75.02    60.02  
             1440x900      74.98    59.90  
             1280x960      60.00  
             1280x800      59.91  
             1152x864      75.00  
             1024x768      75.03    70.07    60.00  
             832x624       74.55  
             800x600       72.19    75.00    60.32    56.25  
             640x480       75.00    72.81    66.67    59.94  
             720x400       70.08  
    DP-1-6 disconnected (normal left inverted right x axis y axis)
    HDMI-1-3 disconnected (normal left inverted right x axis y axis)
            1920x1080 (0x5b) 148.500MHz +HSync +VSync
                                    h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  67.50KHz
                                    v: height 1080 start 1084 end 1089 total 1125           clock  60.00Hz
            1680x1050 (0x5f) 119.000MHz +HSync -VSync
                                    h: width  1680 start 1728 end 1760 total 1840 skew    0 clock  64.67KHz
                                    v: height 1050 start 1053 end 1059 total 1080           clock  59.88Hz
            1280x1024 (0x61) 108.000MHz +HSync +VSync
                                    h: width  1280 start 1328 end 1440 total 1688 skew    0 clock  63.98KHz
                                    v: height 1024 start 1025 end 1028 total 1066           clock  60.02Hz
            1440x900 (0x62) 88.750MHz +HSync -VSync
                                    h: width  1440 start 1488 end 1520 total 1600 skew    0 clock  55.47KHz
                                    v: height  900 start  903 end  909 total  926           clock  59.90Hz
            1280x800 (0x63) 71.000MHz +HSync -VSync
                                    h: width  1280 start 1328 end 1360 total 1440 skew    0 clock  49.31KHz
                                    v: height  800 start  803 end  809 total  823           clock  59.91Hz
            1024x768 (0x67) 75.000MHz -HSync -VSync
                                    h: width  1024 start 1048 end 1184 total 1328 skew    0 clock  56.48KHz
                                    v: height  768 start  771 end  777 total  806           clock  70.07Hz
            1024x768 (0x68) 65.000MHz -HSync -VSync
                                    h: width  1024 start 1048 end 1184 total 1344 skew    0 clock  48.36KHz
                                    v: height  768 start  771 end  777 total  806           clock  60.00Hz
            800x600 (0x69) 50.000MHz +HSync +VSync
                                    h: width   800 start  856 end  976 total 1040 skew    0 clock  48.08KHz
                                    v: height  600 start  637 end  643 total  666           clock  72.19Hz
            800x600 (0x6a) 40.000MHz +HSync +VSync
                                    h: width   800 start  840 end  968 total 1056 skew    0 clock  37.88KHz
                                    v: height  600 start  601 end  605 total  628           clock  60.32Hz
            800x600 (0x6b) 36.000MHz +HSync +VSync
                                    h: width   800 start  824 end  896 total 1024 skew    0 clock  35.16KHz
                                    v: height  600 start  601 end  603 total  625           clock  56.25Hz
            640x480 (0x6f) 31.500MHz -HSync -VSync
                                    h: width   640 start  664 end  704 total  832 skew    0 clock  37.86KHz
                                    v: height  480 start  489 end  492 total  520           clock  72.81Hz
            640x480 (0x70) 30.240MHz -HSync -VSync
                                    h: width   640 start  704 end  768 total  864 skew    0 clock  35.00KHz
                                    v: height  480 start  483 end  486 total  525           clock  66.67Hz
            640x480 (0x72) 25.175MHz -HSync -VSync
                                    h: width   640 start  656 end  752 total  800 skew    0 clock  31.47KHz
                                    v: height  480 start  490 end  492 total  525           clock  59.94Hz
            720x400 (0x73) 28.320MHz -HSync +VSync
                                    h: width   720 start  738 end  846 total  900 skew    0 clock  31.47KHz
                                    v: height  400 start  412 end  414 total  449           clock  70.08Hz

Here I selected one of the disconnected outputs. For this example I am going to use DVI-D-0

If there is no output mode, one can be added with

xrandr --addmode DVI-D-0 1920x1080

# you may use the output you selected and the resolution you want

Next step is to identify the display you are going to use to position your new display. For example, I want to place my virtual display to the left of my primary display, which is HDMI-A-0, so I run the following command:

xrandr --output DVI-D-0 --mode 1920x1080 --left-of HDMI-A-0

# replace DVI-D-0 with the virtual output you selected
# and 1920x1080 with the resolution you chose on the previous command

# other options are --right-of, --above and --below

Finally, when running deskreen:

The virtual display is available (Screen 2).

If you want to disconnect the display, just run:

xrandr --output DVI-D-0 --off

I am willing to do a complete guide and open a pull request if you think it is a good enough method.

The text was updated successfully, but these errors were encountered:

reivilibre · 2021-01-25T07:27:19Z

I think this seems like a good idea! I was a bit amused when I saw the requirement for a Display Dummy Plug, but it kind of defeats the purpose as I'd have to unplug my actual monitor (and buy a dummy) to do that — was thinking that surely this should be doable in pure software, at least on Linux where we should be able to hack around with anything we want...

I'll give this a try :)

DanielMazurkiewicz · 2021-01-25T09:27:43Z

For dummy video drivers check: xvfb and xorg-video-dummy
AFAIK xrandr works on top of one of these

pavlobu · 2021-01-25T11:09:23Z

Hey everyone, I created a discussion thread for sharing knowledge on how to get rid from Display Dummy Plugs: https://github.com/pavlobu/deskreen/discussions/37#discussion-2016522

Feel free to comment there

rugk · 2021-01-25T15:41:13Z

Let me guess, this does not work with Wayland? (as it's called xrandr?)

oetwis · 2021-01-28T22:29:45Z

Edit: I missed a crucial part of the cmd crisszkutnik gave, his solution works for me now and seems like the cleaner approach. I will leave the following here just so interested parties can follow the discussion.

First, thanks for the tool itself and for the trick to use xrandr without a dummy plug.
However, your instructions did not work for me - after executing:

xrandr --addmode DVI-D-0 640x480
xrandr --output DVI-D-0 --right-of HDMI-A-0

I do get the following, as expected:

Screen 0: minimum 320 x 200, current 1680 x 1050, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
HDMI-A-0 connected primary 1680x1050+0+0 (normal left inverted right x axis y axis) 473mm x 296mm
   1680x1050     59.95*+
   1280x1024     75.02    60.02  
   1440x900      59.95  
   1280x800      59.95  
   1152x864      75.00  
   1280x720      59.95  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   640x480       75.00    59.94  
   720x400       70.08  
HDMI-A-1 disconnected (normal left inverted right x axis y axis)
DVI-D-0 disconnected (normal left inverted right x axis y axis)
   640x480       75.00

but deskreen does not show the newly created DVI-D-0.
What did work for me was the following setup:

# --fb: set framebuffer big enough to hold real screen + additional screen to be shared by deskreen
# --panning: 1680x1050 is the actual resolution I want to use, the 2320x1050 (same as fb)
# describes the area in which the mouse may move. Without it, the second screen can be shared in
# deskreen, but the mouse pointer gets stuck at the border of the 'real' screen
xrandr --fb 2320x1050 --output HDMI-A-0 --panning 1680x1050/2320x1050
# create new monitor with 640x480 pixel and 64x48mm phyiscal size, place it right of real screen (1680)
xrandr --setmonitor virtual 640/64x480/48+1680+0 none

This can then be shared with deskreen. xrandr --listmonitors then shows the new 'monitor':

Monitors: 2
 0: +*HDMI-A-0 1680/473x1050/296+0+0  HDMI-A-0
 1: virtual 640/64x480/48+1680+0

and xrandr --delmonitor virtual removes it again.

crisszkutnik · 2021-01-28T23:40:11Z

First, thanks for the tool itself and for the trick to use xrandr without a dummy plug.
However, your instructions did not work for me - after executing:
xrandr --addmode DVI-D-0 640x480
xrandr --output DVI-D-0 --right-of HDMI-A-0

You are missing the mode on the second command. It should be:

xrandr --output DVI-D-0 --mode 640x480 --right-of HDMI-A-0

oetwis · 2021-01-29T19:35:24Z

Thanks!
Now it works properly. And your solution seems like the cleaner one.

logix2 · 2021-02-01T10:54:33Z

Using Nvidia with proprietary drivers (I don't know about Nouveau), xrandr --addmode failas, as seen here. There is a workaround, but it's not great as in my case the mouse cursor flickers using this, and the windows leave trails on the virtual display (so it's not usable). So if anyone knows a workaround for such cases, please let me know.

LJ-Court · 2021-03-20T10:24:03Z

Does anyone know a way to use this with an amd graphics card

MarceloMachadoxD · 2021-05-17T03:24:55Z

is needed to have an free output to it works? here i cant use that to create a virtual screen

physicophilic · 2021-07-28T17:00:42Z

Hey @crisszkutnik I don't have a virtual screen right now. I know using 20-intel.conf I can add it but that seems to be tearing up my screen. I tried using HDMI outputs but the screen stays black. Any suggestions?

MarceloMachadoxD · 2021-08-05T22:10:57Z

Creating a virtual display with xrandr that can be broadcasted as an extra monitor is fairly easy on Linux. I think that this method should be implemented as a guide as it is a viable method for Linux users without the need of extra drivers or a dummy plug. To achieve this I did the following:

First, run the following command:

xrandr

Command output

    DisplayPort-0 disconnected (normal left inverted right x axis y axis)
            DisplayPort-1 disconnected (normal left inverted right x axis y axis)
            DisplayPort-2 disconnected (normal left inverted right x axis y axis)
    HDMI-A-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
             1920x1080     60.00*+  71.91    50.00    59.94  
             1680x1050     59.88  
             1600x900      60.00  
             1280x1024     60.02  
             1440x900      59.90  
             1280x800      59.91  
             1280x720      60.00    50.00    59.94  
             1024x768      70.07    60.00  
             800x600       72.19    60.32    56.25  
             720x576       50.00  
             720x480       60.00    59.94  
             640x480       72.81    66.67    60.00    59.94  
             720x400       70.08  
    DVI-D-0 disconnected (normal left inverted right x axis y axis)
             1920x1080     60.00  
    DP-1-4 disconnected (normal left inverted right x axis y axis)
    HDMI-1-2 disconnected (normal left inverted right x axis y axis)
    DP-1-5 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 531mm x 299mm
             1920x1080     60.00*+
             1680x1050     59.88  
             1280x1024     75.02    60.02  
             1440x900      74.98    59.90  
             1280x960      60.00  
             1280x800      59.91  
             1152x864      75.00  
             1024x768      75.03    70.07    60.00  
             832x624       74.55  
             800x600       72.19    75.00    60.32    56.25  
             640x480       75.00    72.81    66.67    59.94  
             720x400       70.08  
    DP-1-6 disconnected (normal left inverted right x axis y axis)
    HDMI-1-3 disconnected (normal left inverted right x axis y axis)
            1920x1080 (0x5b) 148.500MHz +HSync +VSync
                                    h: width  1920 start 2008 end 2052 total 2200 skew    0 clock  67.50KHz
                                    v: height 1080 start 1084 end 1089 total 1125           clock  60.00Hz
            1680x1050 (0x5f) 119.000MHz +HSync -VSync
                                    h: width  1680 start 1728 end 1760 total 1840 skew    0 clock  64.67KHz
                                    v: height 1050 start 1053 end 1059 total 1080           clock  59.88Hz
            1280x1024 (0x61) 108.000MHz +HSync +VSync
                                    h: width  1280 start 1328 end 1440 total 1688 skew    0 clock  63.98KHz
                                    v: height 1024 start 1025 end 1028 total 1066           clock  60.02Hz
            1440x900 (0x62) 88.750MHz +HSync -VSync
                                    h: width  1440 start 1488 end 1520 total 1600 skew    0 clock  55.47KHz
                                    v: height  900 start  903 end  909 total  926           clock  59.90Hz
            1280x800 (0x63) 71.000MHz +HSync -VSync
                                    h: width  1280 start 1328 end 1360 total 1440 skew    0 clock  49.31KHz
                                    v: height  800 start  803 end  809 total  823           clock  59.91Hz
            1024x768 (0x67) 75.000MHz -HSync -VSync
                                    h: width  1024 start 1048 end 1184 total 1328 skew    0 clock  56.48KHz
                                    v: height  768 start  771 end  777 total  806           clock  70.07Hz
            1024x768 (0x68) 65.000MHz -HSync -VSync
                                    h: width  1024 start 1048 end 1184 total 1344 skew    0 clock  48.36KHz
                                    v: height  768 start  771 end  777 total  806           clock  60.00Hz
            800x600 (0x69) 50.000MHz +HSync +VSync
                                    h: width   800 start  856 end  976 total 1040 skew    0 clock  48.08KHz
                                    v: height  600 start  637 end  643 total  666           clock  72.19Hz
            800x600 (0x6a) 40.000MHz +HSync +VSync
                                    h: width   800 start  840 end  968 total 1056 skew    0 clock  37.88KHz
                                    v: height  600 start  601 end  605 total  628           clock  60.32Hz
            800x600 (0x6b) 36.000MHz +HSync +VSync
                                    h: width   800 start  824 end  896 total 1024 skew    0 clock  35.16KHz
                                    v: height  600 start  601 end  603 total  625           clock  56.25Hz
            640x480 (0x6f) 31.500MHz -HSync -VSync
                                    h: width   640 start  664 end  704 total  832 skew    0 clock  37.86KHz
                                    v: height  480 start  489 end  492 total  520           clock  72.81Hz
            640x480 (0x70) 30.240MHz -HSync -VSync
                                    h: width   640 start  704 end  768 total  864 skew    0 clock  35.00KHz
                                    v: height  480 start  483 end  486 total  525           clock  66.67Hz
            640x480 (0x72) 25.175MHz -HSync -VSync
                                    h: width   640 start  656 end  752 total  800 skew    0 clock  31.47KHz
                                    v: height  480 start  490 end  492 total  525           clock  59.94Hz
            720x400 (0x73) 28.320MHz -HSync +VSync
                                    h: width   720 start  738 end  846 total  900 skew    0 clock  31.47KHz
                                    v: height  400 start  412 end  414 total  449           clock  70.08Hz

Here I selected one of the disconnected outputs. For this example I am going to use DVI-D-0

If there is no output mode, one can be added with

xrandr --addmode DVI-D-0 1920x1080

# you may use the output you selected and the resolution you want

Next step is to identify the display you are going to use to position your new display. For example, I want to place my virtual display to the left of my primary display, which is HDMI-A-0, so I run the following command:

xrandr --output DVI-D-0 --mode 1920x1080 --left-of HDMI-A-0

# replace DVI-D-0 with the virtual output you selected
# and 1920x1080 with the resolution you chose on the previous command

# other options are --right-of, --above and --below

Finally, when running deskreen:

The virtual display is available (Screen 2).

If you want to disconnect the display, just run:

xrandr --output DVI-D-0 --off

I am willing to do a complete guide and open a pull request if you think it is a good enough method.

I need an free real display output?

callegar · 2021-10-17T07:26:07Z

Pretending there is a second monitor with xrandr seems to work. The big issue is that neither the DE nor software that should be able to use it seems to be able to see it.

For instance, on my system (linux, intel graphics) I can get the xrandr --addmode + xrandr --output trick to add a a fake monitor area on the (unused) HDMI-2 port and to place it right of my laptop screen. Then Deskreen sees it.

Unfortunately KDE plasma only partially sees it:

Yes, I can grab windows and move them out of the laptop window to the right, with the right border that stops from being active as a barrier that automaximizes windows that get into it;
Yes, what I grab and move to the space right of my main screen can get transmitted "over the wire" by Deskreen;
But, no, the DE does not work right with it: pop up menus keep appearing on the "real" laptop screen, the desktop pager does not show the enlarged virtual display area (and the system settings do not show the virtual monitor, but this is the lesser problem)

Most important Libreoffice does not see it at all:

It is impossible to get a presentation to play in this virtual monitor keeping the presenter console on the main one or viceversa.

Note that the last point would be quite useful to do presentations with microsoft teams, etc. on linux where you would like to share the virtual screen.

Any clue? Do you really need a virtual HDMI adapter dongle?

MountNoperest · 2021-11-10T19:28:06Z

Thank you so much for this guide!
This worked like magic to my Thinkpad E495 Ryzen 5, KDE Neon 5.23.3 version, with an Ipad Pro 2020. I had to use HDMI-A-0 instead of the DVI, and then tell xrandr that it should replace it with eDP instead of the HDMI-A-0.

xrandr --addmode HDMI-A-0 1920x1080
xrandr --output HDMI-A-0 --mode 1920x1080 left-of eDP

DiamondDemon669 · 2021-11-23T15:51:25Z

I used xrandr --addmode HDMI-2 1920x1080, xrandr --output HDMI-2 1920x1080 --right-of HDMI-1 and it didnt work, but then I ran xrandr --addmode DP-1 1920x1080 and it worked!

I use HP 250 G6 notebook

phuonghuu71 · 2021-12-17T07:18:11Z

Works perfectly <3

SofieTorch · 2021-12-26T21:27:45Z

It was very easy to get it working, thanks!

foxler2010 · 2021-12-29T16:51:45Z

hello! I have a server and want to use my laptop as a display for it. This setup seems nice as i can just split-screen my display into two pieces. The only thing is that I don't want to use deskreen to extend my server display. I can get a VGA output from the server and plug it into the laptop, but the laptop refuses to acknowledge that the server is an input, not an output. Is there a way (using "xrandr" maybe), to tell the virtual second display to take input from my laptop's VGA plug?

w2035 · 2021-12-30T04:45:01Z

It didn't work with my PC lol.
My hardware: AMD 3700x + ASUS b450M pro s, Graphics card: hd6750.And my system is ubuntu 20.04 lts

cvt 1920 1080 60
xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
xrandr --addmode DVI-0 "1920x1080_60.00"
xrandr --output DVI-0 --mode 1920x1080_60.00 --left-of HDMI-0

The command above does generate a virtual display, but the display shared by deskreen is messy.
Both gtf and cvt are the same.

@oetwis I have try his method, It doesn't work for my PC too.

I think my hardware is too old. So it's more convenient for me to buy a graphics card deceiver directly.

GJoe2 · 2022-01-06T23:34:04Z

"you may use the output you selected and the resolution you want"

I tried using Android device resolution (1080x2400) and failed with "xrandr cannot create mode", so I tried instead 1920x1080 and it works. At the end I couldn't select the resolution I want.

I wish I could see second screen with native android device resolution (1080x2400)

tinywrkb · 2022-03-04T11:09:16Z

I haven't tried yet deskreen, but seeing here that WebRTCPipeWireCapturer is mentioned, then something like the following should work for Sway (Wayland) if you have the ScreenCast portal working.
Note that you will to need to click on the invisible screen to select it.

$ swaymsg create_output && swaymsg output "HEADLESS-1" resolution 2048x1536

I actually used this with Sunshine (Moonlight), so it's working there, but the wrong resolution was detected by Sunshine / video compressor, so I still ended up with black bars when streaming to my iPad.

tristan-k · 2022-04-02T12:14:52Z

Is it possible to create a virtual display output on a headless system? For example I'm trying to create a virtual display for qemu/kvm ubuntu 21.10 guest VM but since the VM does not have any display device at all xrandr outputs Can't open display after executing xrandr --addmode DVI-D-0 1920x1080.

Matoo125 · 2022-07-19T15:20:39Z

wonderful works like magic! :)

ilkmin · 2022-08-01T21:31:01Z

In case you don't have any disconnected outputs when you run xrandr, here's a workaround on how to create some for Ubuntu users.

If you're not an Ubuntu user and you don't have evdi packaged, you may follow these steps:

Download the latest release of evdi and unpack it.
cd into the module directory and install it via dkms. Here's a script to automate the process (mind the ver):

#!/bin/bash

if [[ $EUID -ne 0 ]]; then
  echo "Superuser privilege is required, try \"sudo !!\"" 2>&1
  exit 1
fi

name=evdi
ver=1.14.1

cp -r . /usr/src/${name}-${ver}

dkms add -m ${name} -v ${ver}
dkms build -m ${name} -v ${ver}
dkms install -m ${name} -v ${ver}

echo -e "\nFinished."

Load the kernel module:

# modprobe evdi initial_device_count=2

Restart Xorg (simply log out and log back in).
Now run xrandr. You will see disconnected outputs. In my case:

DVI-I-2-2 disconnected (normal left inverted right x axis y axis)
DVI-I-1-1 disconnected (normal left inverted right x axis y axis)

To persist steps 3-4 across reboots, I needed to add this line

evdi

to /etc/modules-load.d/evdi.conf and this line

options evdi initial_device_count=2

to /etc/modprobe.d/evdi.conf.

P.S. @LJ-Court, I believe it answers your question.

tomchor · 2022-11-23T01:01:50Z

Similar to this post I could only make it work with a resolution that's exactly the same as that of my primary monitor.

I set-up a small script to do this as:

virtualdisplayname=DisplayPort-0
resolution=1920x1080 # Same as the laptop's built in monitor

echo "Starting " $virtualdisplayname
xrandr --addmode $virtualdisplayname $resolution
xrandr --output $virtualdisplayname --mode $resolution --left-of eDP
deskreen
xrandr --output $virtualdisplayname --off

So this always works no problem, but when I try to set a smaller resolution (e.g. resolution=1280x720) then I can't make screen extension work. The first steps run fine, the virtual display gets added, deskreen opens, but when I try to connect to the url that deskreen gives me I get a ERR_CONNECTION_REFUSED error.

Is this expected? Is there a workaround?

RusticCraftsman · 2023-01-14T02:16:29Z

This Does not work for me
When entering the following command xrandr --addmode DVI-D-0 1920x1080 I get the following error:
X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 140 (RANDR) Minor opcode of failed request: 18 (RRAddOutputMode) Serial number of failed request: 41 Current serial number in output stream: 42(I do have DVI-D-0 as an option, the 1920x1080 mode does exist)
I have POP Os 22.04 tls
I am using the proprietary drivers, version 515.65.01 (lastest at the time of writing this)

jakre1234 · 2023-01-15T17:27:41Z

My xrandr output just shows two output modes,
eDP-1 connected primary
HDMI-1 connected

I don't have any free outputs, can I still add a virtual screen and connect it to my spare 10" android tablet ? Please help

jakre1234 · 2023-01-16T12:38:44Z

Hello @Elkellympia @tomchor Can you help me, it's urgent.

Thanks and Regards,

RusticCraftsman · 2023-01-16T15:40:09Z

My xrandr output just shows two output modes,
eDP-1 connected primary
HDMI-1 connected

I don't have any free outputs, can I still add a virtual screen and connect it to my spare 10" android tablet ? Please help

Hello @jakre1234 , i do not think so, i found this which may help you achieve that, but it depends on which gpu are you using (i think) , i do not know enough about xorg to help you in this

davigamer987 · 2023-05-02T17:52:02Z

This causes the amdgpu driver to crash for me:

May 02 14:38:01 compooter kernel: ---[ end trace 0000000000000000 ]---
May 02 14:38:01 compooter kernel: RIP: 0010:resource_build_scaling_params+0x124/0x1090 [amdgpu]
May 02 14:38:01 compooter kernel: Code: 02 00 00 00 eb 0c b8 03 00 00 00 eb 05 b8 09 00 00 00 41 89 85 a8 00 00 00 49 8d 7d 10 48 89 54 24 40 48 89 b4 24 98 00 00 00 <8b> 46 54 8b 4e 6c 48 89 7c 24 18 01 86 3c 02 00 00 49 8b 45 08 01
May 02 14:38:01 compooter kernel: RSP: 0018:ffffa454c0bff808 EFLAGS: 00010246
May 02 14:38:01 compooter kernel: RAX: 0000000000000003 RBX: 0000000000000002 RCX: 0000000000000002
May 02 14:38:01 compooter kernel: RDX: ffff94a4ec65e400 RSI: 0000000000000000 RDI: ffff94a4fdf41368
May 02 14:38:01 compooter kernel: RBP: ffffa454c0bff9b8 R08: ffff94a4fdf40af0 R09: ffff94a3c9f60000
May 02 14:38:01 compooter kernel: R10: ffff94a4fdf40ad0 R11: 0000043700000000 R12: 0000000000000005
May 02 14:38:01 compooter kernel: R13: ffff94a4fdf41358 R14: 0000000000000006 R15: ffff94a4fdf401e8
May 02 14:38:01 compooter kernel: FS:  0000000000000000(0000) GS:ffff94a6defc0000(0000) knlGS:0000000000000000
May 02 14:38:01 compooter kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
May 02 14:38:01 compooter kernel: CR2: 0000000000000054 CR3: 00000001a5be2000 CR4: 0000000000750ee0
May 02 14:38:01 compooter kernel: PKRU: 55555554
May 02 14:38:01 compooter kernel: note: kworker/u32:12[190] exited with irqs disabled
May 02 14:38:01 compooter kernel: note: kworker/u32:12[190] exited with preempt_count 1

kudos · 2023-05-21T10:10:05Z

Similar to this post I could only make it work with a resolution that's exactly the same as that of my primary monitor.

I set-up a small script to do this as:
virtualdisplayname=DisplayPort-0
resolution=1920x1080 # Same as the laptop's built in monitor

echo "Starting " $virtualdisplayname
xrandr --addmode $virtualdisplayname $resolution
xrandr --output $virtualdisplayname --mode $resolution --left-of eDP
deskreen
xrandr --output $virtualdisplayname --off
So this always works no problem, but when I try to set a smaller resolution (e.g. resolution=1280x720) then I can't make screen extension work. The first steps run fine, the virtual display gets added, deskreen opens, but when I try to connect to the url that deskreen gives me I get a ERR_CONNECTION_REFUSED error.

Is this expected? Is there a workaround?

I have the exact same problem, and my primary display's resolution (5120x1440) is the reason I'm trying to make this work.

eldaniay · 2023-11-23T21:22:28Z

im getting the error xrandr: Configure crtc 1 failed when running the above commands

tobycm · 2024-01-02T00:56:43Z

Hello,

I am using GNOME and Wayland on Ubuntu

You can make a virtual display by creating a file in ~/.config/systemd/user/org.gnome.Shell@wayland.service.d/persistent-virtual-monitor.conf with content:

[Service]
ExecStart=
ExecStart=/usr/bin/gnome-shell --virtual-monitor 1920x1080 --virtual-monitor 1366x768

And you will have a 1920x1080 and 1366x768 virtual monitor. If you want to disable the monitor, you can turn it off in the settings app.

SwirlyStone5877 · 2024-01-14T22:46:28Z

It gives me an error. I'm using Linux Mint 21.3 on X11. (DP-1 and DP-2 are not placeholders, they are intentional.)

THIS ISSUE HAS BEEN SOLVED.
Thank you, @ absolutelynothelix.

jcleng · 2024-03-10T14:06:56Z

its working! 🎉

xrandr --newmode "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync
# selected disconnected Screen, such as HDMI-1
xrandr --addmode HDMI-1 1920x1080_60.00
xrandr --output HDMI-1 --mode "1920x1080_60.00" --right-of eDP-1
xrandr
# see has * is runing.
# ...
# HDMI-1 disconnected 1920x1080+2880+0 (normal left inverted right x axis y axis) 0mm x 0mm
#    1920x1080_60.00  59.96*
# ...

# Off
xrandr --output HDMI-1 --off


# and use vnc server to use
x11vnc -forever -usepw -display :0

Duvio · 2024-03-28T01:41:42Z

This method just creates an unusable display for me. No matter what windows i drag on this screen, it always stays black. How do i fix this? I want to share it via VNC so that i can use another laptop as the second monitor.

a545254328 · 2024-06-20T18:59:03Z

mark

SerShef · 2024-09-21T12:03:27Z

This Does not work for me When entering the following command xrandr --addmode DVI-D-0 1920x1080 I get the following error: X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 140 (RANDR) Minor opcode of failed request: 18 (RRAddOutputMode) Serial number of failed request: 41 Current serial number in output stream: 42(I do have DVI-D-0 as an option, the 1920x1080 mode does exist) I have POP Os 22.04 tls I am using the proprietary drivers, version 515.65.01 (lastest at the time of writing this)

I HAVE THE SAME OUTPUT WHEN USING --ADDMODE. DID YOU FIND A SOLUTION?

absolutelynothelix · 2024-10-31T23:01:47Z

@SwirlyStone5877, try another output. for example, DP-1 didn't work for me with the same error but HDMI-2 worked.

SwirlyStone5877 · 2024-11-02T02:51:00Z

@SwirlyStone5877, try another output. for example, DP-1 didn't work for me with the same error but HDMI-2 worked.

@absolutelynothelix, hi there. I am grateful for your response, but you were slightly too late. I've gotten a new PC, and everything works as intended out of the box. At least I know how to get things to work on my old PC now. Thank you!

Using xrandr to create a virtual display (Linux) #42

Using xrandr to create a virtual display (Linux) #42

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