.TH XScreenSaver 1 "6-Jan-2022 (6.00)" "X Version 11"
.SH NAME
xscreensaver-systemd - lock the screen upon suspend, and inhibit
screen-blanking during video playback.
.SH SYNOPSIS
.B xscreensaver-systemd [\-\-verbose] [\-\-version]
.SH DESCRIPTION
The \fIxscreensaver\-systemd\fP program is a helper daemon launched by
.BR xscreensaver (1)
for
.BR systemd (1)
or
.BR elogind (8)
integration.  It does two things:
.TP 2
\fB*
When the system is about to go to sleep (e.g., the laptop lid has just been
closed) it locks the screen just \fIbefore\fP the system sleeps, by running
\fIxscreensaver-command \-\-suspend\fP.  When the system wakes up again, it
runs \fIxscreensaver\-command \-\-deactivate\fP to make the unlock dialog appear
immediately.  It does this through the
.BR org.freedesktop.login1 (5)
D-Bus interface.
.TP 2
\fB*
When another process asks for the screen saver to be inhibited (e.g. because
a video is playing) this program periodically runs \fIxscreensaver\-command
\-\-deactivate\fP 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
.BR org.freedesktop.ScreenSaver (5),
.BR org.gnome.SessionManager (5)
and
.BR org.kde.Solid.PowerManagement.PolicyAgent (5)
D-Bus interfaces.
.RS 0
.SH BUGS
Blanking-related problems take two forms: failing to connect to D-Bus; and
other programs requesting stupid things.
.SS D-BUS
Only one program at a time can register with
.BR systemd (1)
or
.BR elogind (8)
for screen-saver-related events, so if another screen saver is running as a
part of the desktop environment, \fIxscreensaver\-systemd\fP 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.
.SS CHROME & CHROMIUM (101.0)
.TP 2
\fB*
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.
.TP 2
\fB*
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.
.PP
Firefox does not have either of these problems.
.SS MPLAYER (2:1.4)
Makes no attempt to inhibit the screen saver.  Use VLC instead.
.SS MPV (0.33)
Makes no attempt to inhibit the screen saver.  Use VLC instead.
.SS 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
\fIxscreensaver\-systemd\fP is a workaround.
.SH SEE ALSO
.BR X (1),
.BR xscreensaver (1),
.BR xscreensaver\-settings (1),
.BR xscreensaver\-command (1),
.BR systemd (1),
.BR sd-bus (3),
.BR elogind (8)
.SH COPYRIGHT
Copyright \(co 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.
.SH AUTHOR
Martin Lucina <martin@lucina.net>, 4-Jun-2019