Hello.
We use Kubuntu as an application server and X2Go and FreeNX as a terminal server.
In Kubuntu 14.04 the session screen doesnt block with kscreenlock app, but in Kubuntu 12.04 kscreenlock work perfect.I got an advise on the X2Go forum to ask the KDE forum how to start kscreenlocker as a daemon. Use xscreensaver isnt the right way since there is the kscreenlock.
Please help.

Kubuntu 14.04 - KDE 4.13.3.
Kubuntu 12.04 - KDE 4.8.5.

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qdbus org.freedesktop.ScreenSaver /ScreenSaver Lock

Do not attempt to run some binary directly.
In more recent versions of KDE, the session is locked by ksmserver (which then invokes the lockscreen GUI process) for security considerations (any attempt to kill the grabbing process will implicitly end the session)

luebking wrote:

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qdbus org.freedesktop.ScreenSaver /ScreenSaver Lock

Do not attempt to run some binary directly.
In more recent versions of KDE, the session is locked by ksmserver (which then invokes the lockscreen GUI process) for security considerations (any attempt to kill the grabbing process will implicitly end the session)

Thanks for the answer.
I know this command, it starts the lock screen in manual mode, but how do I run it automatically?

I'm not sure what you mean by "automaticall" - you mean the "kcmshell4 screensaver" configuration for "automatic" screensaver starting doesn't work? Sounds like quite a bug.

(Please notice that the screenlocker under certain circumstances *cannot* be started, since the input is currently grabbed by another client.
Eg. popups, but also pressed pushbuttons cause this as well as certain kwin effects like "present windows" and the "desktop grid")

luebking wrote:I'm not sure what you mean by "automaticall" - you mean the "kcmshell4 screensaver" configuration for "automatic" screensaver starting doesn't work? Sounds like quite a bug.

(Please notice that the screenlocker under certain circumstances *cannot* be started, since the input is currently grabbed by another client.
Eg. popups, but also pressed pushbuttons cause this as well as certain kwin effects like "present windows" and the "desktop grid")

Command "kcmshell4 screensaver" open a window the setting. I set screen lock after 1 minute and apply the settings. After 3 minutes, the screen is not blocked.

Does the screensaver only not lock or does it not start at all?
Is the "require password after n seconds" item checked (and the timeout set to sth. reasonable)?

If the screen locks by invoking the shortcut, but the "saver" does not start by timeout, something may generate input (mouse/keyboard) events or inhibit the screensaver (video players do so, but I don't know how to query that state)

All goes as expeсted If we start the kscreenlock manualy. The app start and screen locks. Nothing (keyb or mouse) unlock the screen automaticaly. We must use keyb or mouse manually to unlock the screen and enter the pass.
Nothing happens when we set the automaticaly kscreenlock start after some inactivity. The kscreenlock doesnt start at all

I am curious if a solution to "automatically" launching KDE Screen Locker from within an X2GO session has ever been resolved.

I am encountering the same issue. From within an X2GO session, I am also able to launch the KDE Screen Locker manually using either of the following commands:

/usr/lib/kde4/libexec/kscreenlocker_greet --immediateLock
qbdus org.freedesktop.ScreenSaver /ScreenSaver Lock

However, the KDE Screen Lock will not launch automatically (via settings defined withing "kcmshell4 screensaver"). This appears to be an X2GO issue, but I do not know how to debug/resolve. Very puzzling. I have tired "xscreensaver" and that works just fine with KDE4 and X2GO. If I use FreeRDP instead of X2GO, the KDE Screen Lock launches automatically just as one would expect. Although this appears to be isolated to X2GO sessions, I am puzzled why it will launch manually, but not automatically? I would prefer to use the KDE Screen Locker, but I am frustrated that I am not able to get it to work properly within X2GO.

As a test, I replaced "/usr/lib/kde4/libexec/kscreenlocker_greet" with a script that calls "xscreensaver". The XScreenSaver system will launch if "Start automatically after:" is set within the KDE Screen Locker Settings. However, once I switch back to the original executable, nothing works.

I saw this post/thread with the exact same issue and again, curious if a working solution was ever discovered.

Thanks.

I would assume the issue is in KIdleTime.
The preferred idle mechanism seems to depend on the XSYNC extension => check

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xdpyinfo | grep -A50 "number of extensions"

on whether it's available on x2go.
If not, one of the failsafe pollers (xscreensaver) should be used - and is likely buggy.

Thanks for the info.

There is a SYNC extension, but I do not see XSYNC listed. My ".xsession-x2go-errors" log file also contains several of the following error messages:

Xlib: extension "MIT-SCREEN-SAVER" missing on display ":50"

I have confirmed that "MIT-SCREEN-SAVER" is also not listed within the output provided by the suggested "xdpyinfo" command. This certainly seems like an X2GO issue. I will stick with XScreenSaver which seems to work fine - it just doesn't look as nice and does requires modification within each KDE user account. Not a major issue since I do have other options, but was just hoping I could find an easy fix. Doesn't seem likely unless the X2GO developers are able to correct.

Thanks again!

SYNC is the XSYNC extension, but the missing MIT-SCREEN-SAVER extension will be the cause.
Please file a bug against KIdleTime:
https://bugs.kde.org/buglist.cgi?produc ... id=1312634

As requested, I have filed a bug report with KDE. As this issue only occurs when I am connected via X2GO, I have submitted a bug report with the X2GO developers as well. Thanks