If changing the hostname via [code] $ hostname example $ hostname badexample [/code] and locking kde5 plasma session afterwards, kscreensaver complains about being malfunctioning. it recommends switching to a console and executing 'loginctl unlock-sessions' to access the screen again. changing hostname back to the value it was before plasma started fixes the problem. Reproducible: Always Steps to Reproduce: 1. start plasma 2. change hostname 3. lock screen Actual Results: error warning
can you try the binary kscreenlocker_greet with --testing after having changed the hostname? It's in the libexec path.
well ~ > /usr/lib/kscreenlocker_greet --testing No protocol specified QXcbConnection: Could not connect to display :0 [1] 2509 abort (core dumped) /usr/lib/kscreenlocker_greet --testing this happens with a lot of programmes, only a restart of plasma fixes this.
no, sorry, a reset of the hostname fixes this as well.
I can confirm this behaviour on another Archlinux system (intel drivers).
I think the problem is that X11 has problems with the hostname change.
looks like you are right: ~/.Xauthority contains the session cookie to authenticate to the xserver, and it contains the hostname. the same holds for /tmp/xauth-${UID}-0 . updating hostname in the latter seemingly fixes this (but produces errors not mitigated by updating the former file). so, sorry for bugging you guys, but this is not related to kde.
this is not supposed to work, X cannot handle this. however, one can generate a serverinterpreted family xauth entry with [code]xhost +si:localuser:`whoami`[/code]. there are still some warnings, but everything works as expected. this might then be closed as INVALID, NOTABUG or similar.
I remember that there was a watcher for hostname changes in regard to X. Just found a relevant mail thread: http://kde-core-devel.kde.narkive.com/hFmhuy2u/kdelibs-kded-disable-khostnamed-in-kded It might give you some ideas what goes wrong. My understanding of the mail is that changing the host name should not affect X, because the distros ensure it. Maybe something broke.