Blank screen when connected on Linux + Windows

[somerandomguy]

Hi,

Sorry if this has come up before. The search terms that I used seemed to bring up lots of tangentially related things, but not this exactly. This is sort of two issues in one, so bear with me as I try to explain all this.

I have three computers I’m using NoMachine on: two Manjaro Linux w/Gnome desktops and a Windows 10 laptop. All three computers are current with updates, and each is using the latest NM version available to it (v8.8.1 in all three cases). The two desktops are dual-display 1920×1080 monitors, and the laptop has a  17″ 1600×900 screen.

But let’s call the computers Zero, One, and Two, with Two being the Windows laptop. Zero is mainly a media server/NAS type thing. One is my daily driver. Two is a laptop I use for my work and the few oddball Windows programs I need for that. My use is exclusively from One to one of the other PCs.

On all three machines, I have the option for Blank the physical screen when someone connects selected. And it does seem to do that, however:

Issue #1 is that if either/or of Zero and Two are in a “screen off” state (black display, no backlight) when I connect, the screen’s backlight will turn on while display stays black.

(Strangely, despite being set to turn off after 1 minute of inactivity, sometimes when I disconnect from my NM session, the screens on Zero will turn on and stay on indefinitely at the GDM login screen, until/unless I SSH in to it and manually turn them off using export DISPLAY=:0 && sleep 1 && xset dpms force off.)

Issue #2, only applies to Two, the Windows 10 laptop: It will do the same thing (backlight comes on, screen stays black), but I can still see the laptop’s mouse pointer moving around the screen on Two as I do my work from One.

So, the question then is, quite obviously, is there a way to stop either or both of these issues? The first one, I think, may be expected (if unnecessary) behavior. The second one is kind of sort of mildly annoying on the odd chance I happen to notice it, but not at all detrimental to my workflow or anything.

I’m not sure if I should include the specs/logs from one or all three computers, or if there’s debug logging I should activate, or what. If I need to provide more details, let me know and I’ll be happy to do so.

[Britgirl]

Hi, apologies for replying so late.

Issue #1 is that if either/or of Zero and Two are in a “screen off” state (black display, no backlight) when I connect, the screen’s backlight will turn on while display stays black.

You are right. The backlight will turn on at connection and it is expected. No one has ever complained about this behaviour 🙂 but it is a valid point so we are going to add restoring dpms settings at session end.

Issue #2, only applies to Two, the Windows 10 laptop: It will do the same thing (backlight comes on, screen stays black), but I can still see the laptop’s mouse pointer moving around the screen on Two as I do my work from One.

The cursor being visible on windows with screen blanking is something we can’t fix unfortunately.

[Author]

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