mjhjmtu

After my monthly system update, a display manager problem started happening: after logging in (with either slim or lightdm) the root window of the display manager remains on my screen. At first I thought the session had failed to initialise, but while waving my mouse around the screen in hopeless frustration I noticed the mouse cursor was changing as it moused over the expected windows in my session. So I ssh'd in from my laptop and confirmed my session was fine, just "invisible" behind the display manager's root window. Eventually while poking around in my ssh session looking for what might have gone wrong, the screen saver engaged, and when keyboard input disengaged it, there was my desktop session, just fine! Subsequent experimentation determined that CTRL-ALT-F1 then CTRL-ALT-F7 immediately after logging in also causes the session to return to visibility. Any thoughts as to what might be going on?

This issue is different from other similar threads I've so far found here: most threads seem to be talking about desktop applications not starting up correctly. My desktop apps all start fine, they are just invisible behind the root window of the display manager I just logged in from (but not invisible to X, as indicated by the changing mouse pointer.)

Nvidia 396.54 drivers, 4.18.13 kernel on a gentoo distribution with an xfce4 desktop env.

My only thought so far is that session management is supposed to reinitialise the X server and somehow that process is no longer happening. But that's just a thought. No new messages appear in dmesg or /var/log/messages during session startup. For what it's worth here's a capture of what /usr/share/slim/Xsession produces on stdout/stderr:

/usr/share/slim/Xsession: Beginning session setup...
/usr/share/slim/Xsession: Setup done, will execute: /usr/bin/dbus-launch --exit-
with-session /etc/X11/Sessions/Xfce4
/usr/bin/startxfce4: X server already running on display :0.0
gpg-agent[3350]: WARNING: "--write-env-file" is an obsolete option - it has no effect
gpg-agent[3351]: gpg-agent (GnuPG) 2.2.10 started

(xfce4-session:3332): xfce4-session-WARNING **: 08:09:22.446: gpg-agent returned no PID in the variables

(xfsettingsd:3368): xfsettingsd-WARNING **: 08:09:22.745: Property "/Gdk/WindowScalingFactor" has an unsupported type "guint".

(xfce4-session:3332): xfce4-session-WARNING **: 08:09:23.017: failed to run script: Failed to execute child process “/usr/bin/pm-is-supported” (No such file or directory)

** (xfdesktop:3409): WARNING **: 08:09:23.018: Thumbnailer failed calling GetFlavors

(xfce4-session:3332): xfce4-session-WARNING **: 08:09:23.020: failed to run script: Failed to execute child process “/usr/bin/pm-is-supported” (No such file or directory)

(xfce4-session:3332): xfce4-session-WARNING **: 08:09:23.024: failed to run script: Failed to execute child process “/usr/bin/pm-is-supported” (No such file or directory)

(wrapper-2.0:3427): Gtk-WARNING **: 08:09:23.046: gtk_widget_size_allocate(): attempt to allocate widget with width -1 and height 30

(wrapper-2.0:3427): Gtk-WARNING **: 08:09:23.046: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node border, owner GtkFrame)

(wrapper-2.0:3428): Gtk-WARNING **: 08:09:23.056: Negative content width -1 (allocation 1, extents 1x1) while allocating gadget (node button, owner XfceArrowButton)
Fatal Error: Mismatch between the program and library build versions detected.
The library used 3.0 (wchar_t,compiler with C++ ABI 1011,wx containers,compatible with 2.8),
and wxPython used 3.0 (wchar_t,compiler with C++ ABI 1013,wx containers,compatible with 2.8).