[Pkg-xfce-devel] Bug#776674: xfce4-session: xflock4 does not turn off screen due to xset dpms race condition

Chris Bainbridge chris.bainbridge at gmail.com
Fri Jan 30 21:47:49 UTC 2015

Package: xfce4-session
Version: 4.10.1-10
Severity: normal

Dear Maintainer,

/usr/bin/xflock4 does:

for lock_cmd in \
  "xlock -mode blank" \
   set -- $lock_cmd
    if command -v -- $1 >/dev/null 2>&1; then
        $lock_cmd >/dev/null 2>&1 &
        # turn off display backlight:
        xset dpms force off

But it does not work (presumably xset runs too quickly and slock turns the
monitor back on?)

It appears the xset call should be something like:

        sleep 1; xset dpms force off

Using a hardcoded sleep does not seem elegant, but it is the suggested fix at
http://askubuntu.com/questions/38776/trigger-screensaver-off-monitor and

(Also, is there a purpose for doing "set -- $lock_cmd" when the process then
immediately calls exit?)

-- System Information:
Debian Release: 8.0
  APT prefers testing-updates
  APT policy: (500, 'testing-updates'), (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

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

Versions of packages xfce4-session depends on:
ii  libatk1.0-0            2.14.0-1
ii  libc6                  2.19-13
ii  libcairo2              1.14.0-2.1
ii  libdbus-1-3            1.8.12-3
ii  libdbus-glib-1-2       0.102-1
ii  libfontconfig1         2.11.0-6.3
ii  libfreetype6           2.5.2-2
ii  libgdk-pixbuf2.0-0     2.31.1-2+b1
ii  libglib2.0-0           2.42.1-1
ii  libgtk2.0-0            2.24.25-1
ii  libice6                2:1.0.9-1+b1
ii  libpango-1.0-0         1.36.8-3
ii  libpangocairo-1.0-0    1.36.8-3
ii  libpangoft2-1.0-0      1.36.8-3
ii  libpolkit-gobject-1-0  0.105-8
ii  libsm6                 2:1.2.2-1+b1
ii  libwnck22              2.30.7-2
ii  libx11-6               2:1.6.2-3
ii  libxfce4ui-1-0         4.10.0-6
ii  libxfce4util6          4.10.1-2
ii  libxfconf-0-2          4.10.0-3
ii  multiarch-support      2.19-13
ii  xfce4-settings         4.10.1-2
ii  xfconf                 4.10.0-3

Versions of packages xfce4-session recommends:
ii  dbus-x11           1.8.12-3
ii  libpam-systemd     215-10
ii  systemd-shim       9-1
ii  systemd-sysv       215-10
ii  upower             0.99.1-3.1
ii  x11-xserver-utils  7.7+3+b1
ii  xfdesktop4         4.10.2-3
ii  xfwm4              4.10.1-3
pn  xscreensaver       <none>

Versions of packages xfce4-session suggests:
pn  fortunes-mod  <none>
ii  sudo          1.8.10p3-1

-- no debconf information

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