Further research suggests this might be an issue with particular gfx drivers. causing X to die on attempted logout. In case it's relevant, I run an integrated Intel HD4000 and discrete Nvidia GT650M.
Several threads like this http://ubuntuforums.org/archive/index.php/t-1665405.html show that in this case the solution is to add the line TerminateServer=true to the [X-*-Core] section of the file /etc/kde4/kdm/kdmrc in my case this does fix it, though only after a reboot (which I assume triggers the rc to be reread.) I saw indications that other distros either force this TerminateServer in order to work around possible graphics issues - or they intelligently add it when they detect likely incompatibilities. It would be superb if - assuming a more elegant fix is the province of the other team(s) and not Debian - at least this distro could be amended so that the out-of-box behaviour isn't so confusing. Many thanks and any other info needed, let me know. On Tue, Oct 6, 2015 at 11:03 PM, Debian Bug Tracking System < ow...@bugs.debian.org> wrote: > Thank you for the additional information you have supplied regarding > this Bug report. > > This is an automatically generated reply to let you know your message > has been received. > > Your message is being forwarded to the package maintainers and other > interested parties for their attention; they will reply in due course. > > Your message has been sent to the package maintainer(s): > Debian Qt/KDE Maintainers <debian-qt-kde@lists.debian.org> > > If you wish to submit further information on this problem, please > send it to 777...@bugs.debian.org. > > Please do not send mail to ow...@bugs.debian.org unless you wish > to report a problem with the Bug-tracking system. > > -- > 777508: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=777508 > Debian Bug Tracking System > Contact ow...@bugs.debian.org with problems >