Comment 13 for bug 1481330

Most definitely not the lack of the graphics drivers as I have those installed on my machine and have a working Unity 8 desktop session.

Another data point is that this doesn't occur when running against mir_demo_server, but only when running in a Unity 8 desktop session. I start an Xmir instance using a desktop file like the following:

$cat ~/.local/share/applications/xmir-debug.desktop
[Desktop Entry]
Version=1.0
Name=XMir Debug
Exec=Xmir :1
Type=Application
StartupNotify=true
X-Ubuntu-Touch=true

Then from an ssh session, I do something like:
$ DISPLAY=:1 xprop -root

I get the following output:
_XKB_RULES_NAMES(STRING) = "evdev", "pc105", "us", "", ""

But after the command is finished, the Xmir window goes away and the error message I put in the description is printed in ~/.cache/upstart/application-legacy-xmir-debug-blah.log.

The test program that William attached to this bug also produces the same behavior while in a Unity 8 desktop session.

I hope this helps. Also, considering it doesn't occur when running with mir_demo_server, it's probably not a Mir/Xmir issue, but I'm really not sure whose problem it is, but it needs fixing:)