Freedesktop Screensaver API is not implemented

This bug was fixed in the package unity-settings-daemon - 15.04.1+16.10.20160613-0ubuntu1

---------------
unity-settings-daemon (15.04.1+16.10.20160613-0ubuntu1) yakkety; urgency=medium

  [ Marco Trevisan (Treviño) ]
  * PowerManager: connect to keyboard BrightnessChanged signal to update
    the cached current value properly (LP: #1510344)
  * GsdPowerManager: don't cache kbd backlight current value (LP:
    #1583861)
  * common: backport g-s-d commits for having single shared dbus proxies
  * ScreensaverProxy: redirect supported calls to gnome screensaver APIs
    (LP: #1415265, #1584161)

  [ Robert Ancell ]
  * Correctly check value of XDG_CURRENT_DESKTOP.
  * Remove code for disabling plugin under GNOME Shell - they don't use
    u-s-d.
  * Drop print notifications - not used under Unity.

  [ Sebastien Bacher ]
  * power: '0' keyboard backlight is a valid value (LP: #1510344)
  * Don't hit an xerror when a device is removed while being configured
    (LP: #1503758)
  * wacom: don't segfault when a device is removed while being
    configured. (LP: #1439427)
  * power: fix crasher when the plugin is unloaded (LP: #1567116)
  * power: Add sound notification on power plug/unplug

 -- Marco Trevisan (Treviño) <mail@3v1n0.net> Mon, 13 Jun 2016 11:31:26 +0000

Hello Marco, or anyone else affected,

Accepted unity-settings-daemon into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/unity-settings-daemon/15.04.1+16.04.20160701-0ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Running that command still returns the same error.

I checked it in my Xenial install and also using Yakkety daily LiveCD. Both return the error message.

Sorry, I pasted the wrong command. It's now fixed, so please verify this again:

gdbus call --session --dest org.freedesktop.ScreenSaver \
  --object-path /org/freedesktop/ScreenSaver \
  --method org.freedesktop.ScreenSaver.GetActive

The new command returns:

(false,)

Which I assume is how it should be when screensaver is inactive.

This bug was fixed in the package unity-settings-daemon - 15.04.1+16.04.20160701-0ubuntu1

---------------
unity-settings-daemon (15.04.1+16.04.20160701-0ubuntu1) xenial; urgency=medium

  [ Robert Ancell ]
  * Correctly check value of XDG_CURRENT_DESKTOP.

  [ Marco Trevisan (Treviño) ]
  * PowerManager: connect to keyboard BrightnessChanged signal to update
    the cached current value properly (LP: #1510344)
  * GsdPowerManager: don't cache kbd backlight current value (LP:
    #1583861)
  * common: backport g-s-d commits for having single shared dbus proxies
  * ScreensaverProxy: redirect supported calls to gnome screensaver APIs
    (LP: #1415265, LP: #1584161)

  [ Sebastien Bacher ]
  * Don't hit an xerror when a device is removed while being configured
    (LP: #1503758)
  * wacom: don't segfault when a device is removed while being
    configured. (LP: #1439427)

  [ Marco Trevisan (Treviño) ]
  * GsdPowerManager: use proper return value for upower_kbd_toggle
    wherever we use it (LP: #1592816)

  [ Kai-Heng Feng ]
  * SettingsManager: Queue up signals before getting D-Bus connection.
    (LP: #1571640)

 -- Marco Trevisan (Treviño) <mail@3v1n0.net> Fri, 01 Jul 2016 13:28:54 +0000

The verification of the Stable Release Update for unity-settings-daemon has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

Unfortunately, this has escaped regression and reared its ugly head again in Eoan:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 19.10
Release: 19.10
Codename: eoan

$ gdbus call --session --dest org.freedesktop.ScreenSaver --object-path /org/freedesktop/ScreenSaver --method org.freedesktop.ScreenSaver.GetActive

Error: GDBus.Error:org.freedesktop.DBus.Error.NotSupported: This method is not implemented

The same method invocation works with Gnome instead of freedesktop:

$ gdbus call --session --dest org.gnome.ScreenSaver --object-path /org/gnome/ScreenSaver --method org.gnome.ScreenSaver.GetActive
(false,)

According to d-feet "GetActive" exists in both interfaces of the corresponding object path with the same signature.