Cannot detect display running

[jjgalvez]

Hello, I am having issues with NoMachine on Arch. This is a freshly updated system and a brand new install of NoMachine 6.12.3

OS Arch
DE Gnome-shell 3.38
DM GDM 3.38
Wayland 1.18

NoMachine 6.12.3

When I try to log into my server from either a Linux client (also on arch) for from android the error is “Cannot detect any display running” selecting create a new one give “Cannot create a new display”

Thanks in advance for looking into this

 

Attachments:

1. NoMachine-log.tar.gz

[jjgalvez]

Additional information:  This seems to be an issue with Wayland.  If I switch to XOrg nomachine works as expected, but if I am running Wayland NoMachine is unable to find a running display.  Hopefully a workaround which will allow me to switch back to Wayland will be found.  If I can provide any additional logs or help troubleshoot this please let me know.

[kroy]

It looks it’s the same problem mentioned on that post:

https://forums.nomachine.com/topic/connecting-to-manjaro-gnome#post-28140

Please try workaround from @shiba

Modify /etc/pam.d/nx to:

auth       include       system-login
account    include       system-login
password   include       system-login
session    include       system-login

and change DefaultDesktopCommand value in /usr/NX/etc/node.cfg:

DefaultDesktopCommand "/etc/gdm/Xsession 'env XDG_SESSION_TYPE=x11 DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$(id -u)/bus gnome-session'"

[jjgalvez]

Thank you for the reply. The workaround you provided kind of helps. So now when I try to connect to the sever I still get an error saying:

Cannnot detect any display running, Do you want NoMachine to creat a new display and proceed to connect to the desktop?

Selecting yes creates a new XOrg session. I still can not connect to the running Wayland display nor connect to the existing Wayland session. Also I must logout of the NoMachine session to log back into the server locally.

At this time running XOrg seems like a better workaround, Hopefully a solution that allows connecting the WayLAnd display can be found.

[jjgalvez]

Additional information:  Also note that if the user is already logged in NoMachine still creates a new session, but I just get a blank screen. I’m assuming that is because this is the free version which does not support multiple sessions? As stated before If Wayland is turned on NoMachine can not find a display. Disabling Wayland allows it to find and connect to the running display.

[jjgalvez]

Any thing else I can try?

[kroy]

Did you tried to set also DisplayServerExtraOptions "-wlmode compositor" in the /usr/NX/etc/node.cfg? We didn’t have problems with desktop detection when Wayland is enabled. Did you use custom wayland configuration or enable some extensions? Can you try with default settings.

[jjgalvez]

thank you for the reply.  NoMachine still not con not detect my wayland display. I do not have any wayland extensions it is just the standard install. I also completely removed NoMachine and reinstalled (mainly to make sure I had not done something goofy to the config files that I didn’t remember).

With both the out-of-the-box install and with the DisplayServerExtraOptions set to “-wlmode composter” NoMachine can not detect my display, nor can it create a new wayland display.

Trying to create a new server shows the attached error.

OS Arche
DM gmd 3.38.1
DE gnome-shell 3.38.1
composter mutter 3.38.1
display server wayland 1.18.0

Attachments:

1. out.txt

[Britgirl]

We’ve managed to reproduce it and opened a Trouble Report. Please sign up to receive notification of the fix at the following link:

NoMachine server cannot detect Wayland local display on Arch Linux
https://www.nomachine.com/TR10R09881

[Gobelet]

Hello,

I can confirm I’m getting the same issue with Fedora 33 (RC, the final version is slated on Tuesday).

Fedora 33 RC with NoMachine (free) 6.12.3, connection to a physical machine

gdm-3.38.1-1.fc33
gnome-shell-3.3.1-2.fc33
mutter-3.38.1-1.fc33
pipewire-0.3.13-4.fc33

Here’s the output when I try to sudo /usr/NX/bin/nxserver --restart:

NX> 111 New connections to NoMachine server are enabled.
NX> 161 Enabled service: nxserver.
NX> 162 WARNING: Cannot find X servers running on this machine.
NX> 162 WARNING: A new virtual display will be created on demand.
NX> 161 Enabled service: nxd.

[jjgalvez]

That’s great to hear! I’ll follow the TR

[jjgalvez]

Wanted to provide an update to this topic.  It seems that NoMachine is again running under with Wayland gnome on Arch. Since there has not been a NoMachine update I’m assuming that it was some form of gnome regression that caused the issue. To verify I did a complete fresh install of NoMachine removing all my old configurations and it worked out of the box. My current configuration is as follows:

NoMachine: 6.12.3
DM gdm: 3.38.2
DE gnome-shell: 3.38.2
composter  mutter: 3.38.2

[jjgalvez]

Interesting observation. Setting GDK_BACKEND=wayland in /etc/environments prevents NoMachine from starting properly.

[Britgirl]

Hello, since the most recent version is now 7.0.211, I suggest you update to this (which also fixes the TR which is linked above) and if there is any unusual behaviour, let us know by opening a new topic. Thanks! 🙂

[jjgalvez]

Thank you if I see anything unusual with 7.0.211 I will open a new topic.

[Author]

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