Bug 1558740

gnome-screensaver is not running but gsd-screensaver-proxy is.

GNOME no longer uses gnome-screensaver for screen locking, so this is to be expected.  Desktops which wish to use this need to assure that it is autostarted with the session (as in GNOME Flashback from my COPR).

Well, gnome allows configuring a screensaver which does not work so if it is not a gnome screensave, then what?

GNOME Shell (the component which provides the GNOME default and classic desktops nowadays) handles screen locking itself and does not use gnome-screensaver.  Since gnome-screensaver is not being used, gnome-screensaver-command will have no effect.

This is perfectly fine but the changes in gnome-control-center should work and they do not - no screensaver is called. How do I verify that the default gnome screensaver is configured properly and running? gsd-screensaver-proxy does not have man pages.

super+L does not lock the workstation either, does this information help?

This comes up when super-L fails:

Mar 22 16:41:35 localhost.localdomain gsd-media-keys[2057]: Couldn't lock screen: Cannot invoke method; proxy is for a well-known name without an owner and proxy was constructed with the G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START flag

lightdm is used, not gdm.
light-locker was not installed, installation did not change a thing.

I believe that's expected that screen locking needs gdm and does not work with lightdm.

The gnome-control-center could detect this and hide the settings or something in order to give the user a clue that something is not going to work... Or is it a bug for bugzilla.gnome.org?

This message is a reminder that Fedora 27 is nearing its end of life.
On 2018-Nov-30  Fedora will stop maintaining and issuing updates for
Fedora 27. It is Fedora's policy to close all bug reports from releases
that are no longer maintained. At that time this bug will be closed as
EOL if it remains open with a Fedora  'version' of '27'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 27 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

I finally just found this bug report, although I also ran into this problem in Fedora 27. I can confirm that the bug remains in both Fedora 28 and now Fedora 29.

Under Fedora 27, I had switched from gdm to lightdm because of gdm login screen issues that I could not resolve. Since lightdm solved my login issues, I decided at that time to live with gnome-shell screensaver/screen locking controls that had no effect.

I don't know what the Gnome philosophy is regarding alternate display managers, but I think that if gnome-shell provides controls that are *only* effective with gdm, then it should hide those controls or note that they are ineffective when another display manager is in use.

(In reply to Chris Burghart from comment #12)
> I finally just found this bug report, although I also ran into this problem
> in Fedora 27. I can confirm that the bug remains in both Fedora 28 and now
> Fedora 29.
> 
> Under Fedora 27, I had switched from gdm to lightdm because of gdm login
> screen issues that I could not resolve. Since lightdm solved my login
> issues, I decided at that time to live with gnome-shell screensaver/screen
> locking controls that had no effect.
> 
> I don't know what the Gnome philosophy is regarding alternate display
> managers, but I think that if gnome-shell provides controls that are *only*
> effective with gdm, then it should hide those controls or note that they are
> ineffective when another display manager is in use.

P.S. I have just switched back to gdm (which no longer has the login issue from Fedora 27), and now have functioning screen locking again.

Fedora 27 changed to end-of-life (EOL) status on 2018-11-30. Fedora 27 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.