[arch-general] Blue/Black Screen of Death with Plasma5

[Dutch Ingraham]

Hi folks-

The backstory:  I bought a new el-cheapo multi-function printer-scanner
today and as a consequence installed sane, xsane, and
kdegraphics-ksaneplugin.  I did all that while logged into my usual
window manager, dwm.  All was fine.

Then I wanted to try the kde plugin, so logged into kde desktop and was
presented with what appeared to be the blue screen of death (sometimes
black).  Plasma seems to start fine, i.e., splash screen goes through
its usual motions, then the blue/black screen appears when the desktop
usually does.

However, not was all as it seemed.  The entire kde suite works, i.e.,
mouse and keyboard, and most, but not all, applications (although to
access them I need to alt-F2 and run them manually.)  The only thing
that does not seem to work is the desktop itself.

I cannot say the packages I installed today are the cause - it could be
any update within the last two weeks; as noted, I rarely log into the
kde desktop.

My uname -a is:

Linux arch 4.2.3-1-ARCH #1 SMP PREEMPT Sat Oct 3 18:52:50 CEST 2015
x86_64 GNU/Linux

My desktop is: plasma-desktop-5.4.2-1

As you can imagine, there are no shortage of google results regarding
the blue/black screen. However, there was nothing current enough or
otherwise useful. [1][2][3]

Here's what I've tried so far, in no particular order:

1. removed kdegraphics-ksaneplugin;
2. re-installed plasma-desktop;
3. downgraded kactivities-frameworks;
4. removed ~/.kde and /tmp/kde-dutch.


Logs don't show anything of importance (as I would expect, as Xorg
starts and runs properly.)  Top shows kwrapper5, dbus, polkit,
kdeinit5, klauncher, kded5, kactivitymanager, etc., all running.

Any suggestions are greatly appreciated;  If further information is
needed, please let me know.



[1] https://bbs.archlinux.org/viewtopic.php?id=143124
[2] https://forum.kde.org/viewtopic.php?f=67&t=118151
[3] https://bbs.archlinux.org/viewtopic.php?id=193286