Bug#826187: Fwd: xfce4 second monitor does not wake up after suspend, with kernel 4.5.0-1 or 4.5.0-2

[Jasper Taylor <jasper@simulistics.com>]

Package: xfce4
Version: 4.12.5
Followup-For: Bug #826187

Dear Maintainer,

If I suspend the session using the 'log out' dialogue, or if it suspends due to
a period of inactivity, then it restarts properly with both screens. But I have
a power management setting to suspend the session on closing the laptop lid. If
I do this, then reopen the lid and hit the power button to resume the session,
I get the exact bug described by the OP -- the external monitor starts up but
the built-in screen of the laptop does not. In my layout the external monitor
is above the built-in screen, and if the pointer is moved to the bottom, it
shows at the top of the laptop screen but nothing else is displayed there. The
pointer cannot be moved further down.

The taskbar widget showing the workspaces still behaves as if the laptop screen
were part of the desktop area. If the display settings dialogue is open on the
external monitor when the machine suspends, or if it can be opened after
resuming, the laptop screen starts working normally again. However, it may open
on the non-working laptop screen (as shown by the workspace thumbnail) in which
case the only way to restart the screen is to log out.



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

Kernel: Linux 4.19.0-2-amd64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8), LANGUAGE=en_GB:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages xfce4 depends on:
ii  gtk2-engines-xfce        3.2.0-4
ii  libxfce4ui-utils         4.12.1-3
ii  thunar                   1.8.4-1
ii  xfce4-appfinder          4.12.0-2
ii  xfce4-panel              4.12.2-1
ii  xfce4-pulseaudio-plugin  0.4.1-1
ii  xfce4-session            4.12.1-6
ii  xfce4-settings           4.12.4-1
ii  xfconf                   4.12.1-1
ii  xfdesktop4               4.12.4-2
ii  xfwm4                    4.12.5-1

Versions of packages xfce4 recommends:
ii  desktop-base      10.0.0
ii  tango-icon-theme  0.8.90-7
ii  thunar-volman     0.9.1-1
ii  xfce4-notifyd     0.4.3-1
ii  xorg              1:7.7+19

Versions of packages xfce4 suggests:
pn  gtk3-engines-xfce    <none>
ii  xfce4-goodies        4.12.6
ii  xfce4-power-manager  1.6.1-1

-- no debconf information