Barry_IA

[Barry_IA]

Hi Britgirl!

Attached (hopefully!) the log.  May have found a problem:  the Collect Logs knowledgebase says the command is nxserver –debug — enable all.  My Linux (Ubuntu 22.04) system was not able to find nxserver (which nxserver –>  no result).  Instead needed the full path: sudo /usr/NX/bin/nxserver --debug --enable all (as well as requiring ‘sudo’); same for the other commends.  May or may not be a clue as to why my issue.

And now for the log…..

Thanks! Barry

Attachments:

1. NoMachine-log-2025.04.09-15.28.01.zip

[Barry_IA]

Hi Britgirl!

Thanks for the updated suggestion! In the meantime what I tried. (Will get back to the “Connecting to Linux headless machines with NoMachine” knowledgebase article after.)

The original ‘wiring diagram’:

DisplayPort (DP) → DP to HDMI cable → HDMI-to-AV adapter → 4.3” monitor

HDMI → HDMI switch → 17” monitor

(4.3” monitor is always on; 17” monitor switched in when something noted going on but not all that comfortable to work at.)

The two monitors show the same display.

Try #1:

Add HDMI splitter:

DisplayPort (DP) → DP to HDMI cable → Splitter → HDMI-to-AV adapter → 4.3” monitor

                                                                                  |

                                                                                    → Dummy Monitor

Result: Dummy Monitor’s LED on; 4.3” monitor just gave ‘no signal colour bars’. Not useful to me.

Try #2:

Add HDMI splitter:

HDMI →Splitter → HDMI switch → 17” monitor

                      |

                        → Dummy Monitor

Result: Dummy Monitor’s LED on; 17” monitor blank (so some sort of signal captured).

NoMachine still giving virtual screen.

OK, on to “Connecting to Linux headless machines with NoMachine” knowledgebase (https://kb.nomachine.com/AR03P00973)

What to do if you see a black or white screen or the screen is frozen

A specific case which leads to various symptoms (e.g. black screen or white screen or frozen screen) on Linux is when the X server is running but it is not rendering because the video card is turned off. In this case NoMachine doesn’t use its own virtual display because it detects that the X server running.

I’m thinking the video card (built in to the CPU should that detail make a difference) is on/active as I get active video: clock updates, etc. (Both the DP/4.3” monitor and the HDMI outputs.)

1) Use a X virtual framebuffer

…Well, at the end of the section says “will create own virtual frambuffer” and it seems like that’s what it’s doing now.

2) Use a fake display dongle

Tried that (above ramblings). ..Well, I didn’t try directly (no splitter).

For the Enterprise Desktop: how to enable the creation of NoMachine display service

(Section mentions ‘virtual display’, plus I don’t think I’m ‘Enterprise’ – as long as I don’t let the smoke out! ….)

/usr/NX/etc/server.cfg

CreateDisplay Originally commented and 0

Try: uncomment and 1 (per KB instructions)

DisplayOwner Originally commented and “”

Try uncomment, and USERNAME – no double quotes

In the cfg were comments on setting DisplayGeometry if reset the CreateDisplay but down in that section said default is 1280×800 which I’m figuring should work fine with the display; left commented.

NoMachine was not connected to an remote devices; also did sudo /etc/NX/nxserver --restart just in case.

Ah poop! NoMachine giving same virtual screen as before. Will copy my cfg backup back in.

Do you want me to do the extract logs step or have something else in mind?

And thanks for reading through all this: I tend to be overly detailed but so the person helping knows what I am doing/seeing on my side.

Thanks again!

Barry

[Barry_IA]

Hi Britgirl!

Thanks for the clarification on server and client — I was correct but didn’t want to misstate and confuse.

My two machines in question are — umm — ‘semi-headless’ which probably means NoMachine sees them as headless and so creates the virtual monitor – things are starting to make sense!   By ‘semi-headless’ they have a tiny monitor connected, but via a HDMI to AV adapter — bet no EDID.  A second monitor connection goes to a HDMI switch — know that doesn’t get an EDID signal unless the switch is set to that input.

(The ‘tiny’ monitor is 4″, basically just to keep an eye on things.  The HDMI switch selects amongst several computers, connects to a full-size monitor, and is the one used if I need to do work.)

I’ve got a potential work-around in mind now that I have been told why the problem is occurring.  Thanks! Barry

[Author]

Posts