Ubuntu Manpage: xscreensaver-systemd - lock the screen upon suspend, and inhibit screen-blanking during video playback.

Provided by: xscreensaver_6.08+dfsg1-1ubuntu4_amd64

NAME

       xscreensaver-systemd - lock the screen upon suspend, and inhibit screen-blanking during video playback.

SYNOPSIS

       xscreensaver-systemd [--verbose] [--version]

DESCRIPTION

       The  xscreensaver-systemd  program  is  a  helper  daemon  launched  by xscreensaver(1) for systemd(1) or
       elogind(8) integration.  It does two things:

       * When the system is about to go to sleep (e.g., the laptop lid has just been closed) it locks the screen
         just before the system sleeps, by running xscreensaver-command --suspend.  When  the  system  wakes  up
         again, it runs xscreensaver-command --deactivate to make the unlock dialog appear immediately.  It does
         this through the org.freedesktop.login1(5) D-Bus interface.

       * When  another  process asks for the screen saver to be inhibited (e.g. because a video is playing) this
         program periodically runs xscreensaver-command --deactivate to keep the display  un-blanked.   It  does
         this   until  that  other  program  asks  for  it  to  stop,  or  exits.   It  does  this  through  the
         org.freedesktop.ScreenSaver(5),                     org.gnome.SessionManager(5)                     and
         org.kde.Solid.PowerManagement.PolicyAgent(5) D-Bus interfaces.

BUGS

Blanking-related problems take two forms: failing to connect to D-Bus; and other programs requesting
stupid things.

D-BUS
Only one program at a time can register with systemd(1) or elogind(8) for screen-saver-related events, so
if another screen saver is running as a part of the desktop environment, xscreensaver-systemd will be
unable to launch. This program has workarounds for Gnome and KDE, but if you are using something else,
that might be a problem.

CHROME & CHROMIUM (101.0)
* Playing only audio in Chrome will prevent your screen from blanking. Chrome sends the exact same
"inhibit" reason for audio as for video, so we can't tell them apart.

* Chrome prevents your screen from blanking when playing short, looping videos. This means that your
screen won't blank when Chrome is showing a Twitter page (because those animated GIFs aren't really
GIFs, they are MP4s). This affects Tweetdeck as well.

The proper way to fix this would be for Chrome to stop inhibiting once a video loops. That way your
multi-hour movie inhibits properly, but your looping GIF only inhibits for the first few seconds.

Firefox does not have either of these problems.

MPLAYER (2:1.4)
Makes no attempt to inhibit the screen saver. Use VLC instead.

MPV (0.33)
Makes no attempt to inhibit the screen saver. Use VLC instead.

VARIOUS
Most programs fail to re-enable screen blanking if they crash or are killed while playing. We try to
detect when this has happened, but that might not work with all versions of systemd, resulting in screen
blanking remaining permanently disabled. If that happens, killing and restarting xscreensaver-systemd is
a workaround.

COPYRIGHT

       Copyright  ©  2019-2022  by  Martin  Lucina  and Jamie Zawinski.  Permission to use, copy, modify, and/or
       distribute this software for any purpose with or without fee is hereby granted, provided that  the  above
       copyright notice and this permission notice appear in all copies.

       The  software  is  provided  "as is" and the author disclaims all warranties with regard to this software
       including all implied warranties of merchantability and fitness. in no event shall the author  be  liable
       for any special, direct, indirect, or consequential damages or any damages whatsoever resulting from loss
       of  use,  data or profits, whether in an action of contract, negligence or other tortious action, arising
       out of or in connection with the use or performance of this software.

AUTHOR