Bug#794242: gnome-screensaver: Invoking "gnome-screensaver-command -l" over SSH no longer locks screen

[Hugo Cardozo]

Package: gnome-screensaver
Version: 3.6.1-4
Severity: important

Dear Maintainer,

Up until Wheezy, I used often the "remote locking" facility of
gnome-screensaver-command. That's when you ssh-login on your box and execute:

user$ DISPLAY=:0 gnome-screensaver-command -l

Then on my android phone I installed one of that many apps which lets you run 
remote commands with just a tap. So I could remote-lock my desktop if needed.

But now that I upgraded to Jessie, that stopped working.

The command "gnome-screensaver-command -l" works when I invoke it when on Gnome
desktop (gnome-terminal, xterminal, ALT-F2, etc). 

But when I invoke that command:

user$ DISPLAY=:0 gnome-screensaver-command -l

whether I try it from the console or over SSH, it does nothing. The screen
does not lock. I don't get error messages, nor any kind of output.


-- System Information:
Debian Release: 8.1
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.16.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=es_PY.utf8, LC_CTYPE=es_PY.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnome-screensaver depends on:
ii  dbus-x11                   1.8.18-0+deb8u1
ii  gnome-icon-theme           3.12.0-1
ii  gnome-session-bin          3.14.0-2
ii  gsettings-desktop-schemas  3.14.1-1
ii  libc6                      2.19-18
ii  libcairo2                  1.14.0-2.1
ii  libdbus-1-3                1.8.18-0+deb8u1
ii  libdbus-glib-1-2           0.102-1
ii  libgdk-pixbuf2.0-0         2.31.1-2+b1
ii  libglib2.0-0               2.42.1-1
ii  libgnome-desktop-3-10      3.14.1-1
ii  libgnomekbd8               3.6.0-1
ii  libgtk-3-0                 3.14.5-1
ii  libpam0g                   1.1.8-3.1
ii  libsystemd0                215-17+deb8u1
ii  libx11-6                   2:1.6.2-3
ii  libxext6                   2:1.3.3-1
ii  libxklavier16              5.2.1-1
ii  libxxf86vm1                1:1.1.3-1+b1

Versions of packages gnome-screensaver recommends:
ii  gnome-power-manager   3.14.1-1
ii  libpam-gnome-keyring  3.14.0-1+b1

gnome-screensaver suggests no packages.

-- no debconf information