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

Provided by: xscreensaver_6.08+dfsg1-1ubuntu3_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