Kubuntu 26.04 black screens when multiple display cards with monitors

[Britgirl]

Did you restart the NoMachine server after changing the WaylandModes key? If you did, send us a new set of logs from the Kubuntu machine.

[timok]

Here are the server logs.
Sequence:

server node.cnf has WaylandModes drm,egl,compositor
reboot server
connect from remote (all screens black)
Save server logs

 

Attachments:

1. Server-logs-2026-06-04-03.18.42.zip

[Britgirl]

We looked at the logs and it’s as if the suggested option wasn’t set. Did you set it in server side node.cfg? Can you send us the node.cfg file from the server side to check?

[timok]

Yes, the setting is set at the computer that has those 8 displays and where the server log was taken. There are three node.cfg in the server: /etc/NX/server/localhost/node.cfg, /usr/NX/scripts/etc/localhost/node.cfg and /usr/NX/etc/node.cfg The last one has all the settings so I edited that. The two other ones seem to have only pointer to path /usr/NX (NodeRoot = “/usr/NX”). Find attached the last one. .

Attachments:

1. node.zip

[fra81]

Hi,

you edited the correct file but please remove the spaces in “drm, egl ,compositor”. The exact line should look like:

WaylandModes drm,egl,compositor

Then restart the NoMachine server.

[timok]

Here are the server logs with updated settings. Booted, connected from client and disconnected.

Still all screens showing black.

 

Attachments:

1. Server-logs-2026-06-11-07.18.10.zip

[Bilbotine]

Hi timok,

Thanks for sending the logs. Unfortunately we are not able to reproduce the issue in our labs.

Would you be willing to install a debug package and help us investigate further ?

[timok]

Yes, please provide instructions about installing debug package.

[Bilbotine]

Hi timok,

Please check your mailbox, we sent you an email with instructions.

Kind regards,

[Britgirl]

Hi, we got the logs, but we need you to send fresh set. It’s important to revert the WaylandModes key to its default value, i.e. ‘egl,drm,compositor’ (or just comment out the key). Then restart the NoMachine server, reproduce, and send logs again. Apologies if this was not made clear. Thanks.

[timok]

New logs sent with suggested changes.

[Britgirl]

Hello,

thanks for your patience. We analyzed the logs, but they don’t show any error, nor give an indication of where the error could be. To proceed further, we would like to see logs from both the working and the non-working case, so that we can compare them.

[timok]

I tested with the debug version nomachine_9.6.3_15_amd64_debug_dma.deb but that did not work at all anymore, always just black. Probably due to latest updates to Kubuntu 26.04.
I updated the NoMachine to 9.7.3. Then it works as before: all working fine when 4 monitors connected to one display card and all black when just one additional monitor was connected to second display card.

I have now logs from both cases but they exceed the maximum file size for attachment:
-rw-r–r–  1 am-operator am-operator  2.4M Jul  8 01:26  ‘Server logs 2026-07-08 01.26.37.zip’
-rw-r–r–  1 am-operator am-operator  2.4M Jul  8 01:30  ‘Server logs 2026-07-08 01.30.42.zip’

Please provide a way to send bigger logs. I can also run with debug version of 9.7.3 if you provide one.

[Britgirl]

Hi, you can send the logs to forum[at]nomachine[dot].com. Please use the title of this topic as the subject of your email. Thanks!

[Author]

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