Hi,

I have a (probably) stupid question:

Is it possible (ideally in KDE) to lock the screen (i.e. not accept any inputs unless a username/password is provided) but still show the desktop? I'm not sure if "kiosk-mode" is the right word but that is what comes to mind.

I'm asking because I want to display stats on my monitor (one website and the KDE system monitor) but I don't want anyone to be able to interact with the machine unless they provide a valid username/password combination.

So far, I have not found out if this is possible. When I lock the screen in KDE, it shows the lockscreen (obviously), so I can't see my desktop. What I want is to show my desktop but if someone presses a key or moves the mouse, a password prompt should appear.

Does something like this exist?

Thanks in advance for any answers!

I don't think it is possible. I have mucked about with a number of DEs--certainly all the major ones--and have not yet encountered a lock screen that did in some way blank the monitor or obscure the display.

The purpose of lock screen is not just to prevent others from using the machine, it's also to prevent others from seeing what's on the screen (think of computers in a work environment where confidential information may be on the screen when someone dashes off to lunch).

Just my two thoughts.

if you want to do that you need to implement a screen saver (which will run while the screen is locked) and display whatever you want.

s/The/A/

I can guarantee that it's possible - though I can't say how much work it will take.


rokyo401 - a few things to try:

Perhaps produce a 24-bit PNG with transparency and allocate it as the background image - probably it'll be overlaid on a plain background, but maybe the alpha channel will be applied and it'll continue to show the stuff behind.

Alternatively, if you're ok with compiling code, see what happens if you take a simple locker like slock and make the "lockscreen" function a no-op; it should still lock input, and might not obscure the display.

If all input is via USB and you have remote access to the machine, disabling the USB module in the kernel (modprobe) might be a valid choice.

Or... try xtrlock which aims to do exactly as requested: Lock X display until password supplied, leaving windows visible - the man page mentions issues on Wayland and that "some keyboard shortcuts may also continue to function", so you'll want to thoroughly test it before using it in a context where that matters.

Yes, that's what the lock screen is usually supposed to do. But this is about a machine that displays information that is needed to be seen by several people throughout the day, while these same people are not supposed to be able to interact with the machine or even the website that it displays. Kind of like those LED billboards at bus stations that display arrival times... just as a regular monitor displaying a website (and an app).

I could probably just physically lock the PC in some enclosure and only have the cable for the monitor come out of the enclosure, but the machine also regularly needs to be interacted with by personnel who has the password. Still would make me more comfortable if the machine was also locked in software. :-/

The man page sounds pretty much like what I need. I think I remember something like this from an old Solaris maybe. I definitely have seen the cursor turning into a lock somewhere before.... ;-)