<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Thiago,<div class=""><br class=""></div><div class="">Thank you for the suggestion!</div><div class=""><br class=""></div><div class="">I should have come back and update my findings. In my case, dbus disconnection</div><div class="">is caused by <a href="https://src.fedoraproject.org/rpms/kde-settings/blob/34266bc9b362b3db9f0ef5c7e4a3d0154a02f8a9/f/99-restart-dbus.sh" rel="nofollow noreferrer noopener" target="_blank" class="">99-restart-dbus.sh</a> in Fedora 33 plasma-workspace, which is added recently.</div><div class="">This script is triggered by plasma-shutdown and it restarts dbus-broker after 8 seconds.</div><div class=""><br class=""></div><div class="">But for kwin_x11 itself, it never exits, as XCB_SELECTION_CLEAR is never triggered.</div><div class="">I am working on merge request <a href="https://invent.kde.org/plasma/kwin/-/merge_requests/438" class="" style="white-space: nowrap; font-family: -apple-system, system-ui, "Segoe UI", Roboto, "Noto Sans", Ubuntu, Cantarell, "Helvetica Neue", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"; orphans: 2; widows: 2; box-sizing: border-box; color: rgb(48, 48, 48); text-decoration: none; transition: background-color 100ms linear 0s, color 100ms linear 0s, border 100ms linear 0s;">!438</a> to find a better solution to terminate kwin_x11</div><div class="">before dbus gets restarted (or never restarted).</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Thank you for your help!</div><div style=""><br class=""><blockquote type="cite" class=""><div class="">On Nov 11, 2020, at 21:32, Thiago Macieira <<a href="mailto:thiago@kde.org" class="">thiago@kde.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">On Sunday, 8 November 2020 08:16:37 PST Sheng Mao wrote:<br class=""><blockquote type="cite" class="">Thank you for explaining this, Thiago!<br class=""><br class="">Then it means the unregistration code kwin_x11 will not be executed.<br class="">Although I still don’t know who/why terminates the session but it is<br class="">something I can use.<br class=""></blockquote><br class="">You can debug to find out the order in which events are happening. Does <br class="">kwin_x11 exit before the dbus-daemon exits? Or does the daemon exit first, <br class="">thus causing kwin_x11 to quit?<br class=""><br class="">And is there sufficient time for dbus-daemon to notice other applications' <br class="">exit and send service name deregistration signals? If all the processes are <br class="">terminated too quickly, dbus-daemon may react to its termination before <br class="">handling all the sockets.<br class=""><br class=""><blockquote type="cite" class="">* in kwin_x11, I need to add a watcher for session disconnected, and close<br class="">kwin_x11 event loop on that<br class="">* in startkde, I need to add a timer to query registration status. My test<br class="">app shows that the service becomes unregistered after a few seconds.<br class="">QDBusServiceWatcher cannot send a unregistration event/signal if<br class="">org.kde.KWin is terminated passively.<br class=""><br class="">Thank you! I will do more tests on that.<br class=""></blockquote><br class="">You should simply react to the Disconnected signal and handle that as a <br class="">deregistration of every single service name.<br class=""><br class="">Note you can't send anything to D-Bus any more.<br class=""><br class="">-- <br class="">Thiago Macieira - thiago (AT) <a href="http://macieira.info" class="">macieira.info</a> - thiago (AT) <a href="http://kde.org" class="">kde.org</a><br class=""> Software Architect - Intel DPG Cloud Engineering<br class=""><br class=""><br class=""><br class="">_______________________________________________<br class="">dbus mailing list<br class=""><a href="mailto:dbus@lists.freedesktop.org" class="">dbus@lists.freedesktop.org</a><br class="">https://lists.freedesktop.org/mailman/listinfo/dbus<br class=""></div></div></blockquote></div><br class=""></body></html>