From: Fix gnome-session registration placement
Subject: [PATCH] main: Notify gnome-session when we're ready

gnome-session's builtin service manager needs gnome-shell to call
RegisterClient so it knows shell startup is complete. Without XSMP,
this D-Bus call is the only way to signal readiness.

Place the notification right after sd_notify() and notify_ready(),
during initialization - not in the shutdown handler.
---
 js/ui/main.js | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

--- a/js/ui/main.js	2026-03-15 11:01:20.000000000 +0000
+++ b/js/ui/main.js	2026-03-19 15:05:27.806379161 +0000
@@ -314,6 +314,7 @@
     GLib.idle_add_once(GLib.PRIORITY_DEFAULT, () => {
         Shell.util_sd_notify();
         global.context.notify_ready();
+        _notifyGnomeSessionReady();
     });
 
     _startDate = new Date();
@@ -379,6 +380,23 @@
     });
 }
 
+async function _notifyGnomeSessionReady() {
+    try {
+        let startupId = GLib.getenv('DESKTOP_AUTOSTART_ID');
+        if (!startupId)
+            startupId = '';
+        let params = GLib.Variant.new('(ss)', ['org.gnome.Shell.desktop', startupId]);
+        await Gio.DBus.session.call(
+            'org.gnome.SessionManager',
+            '/org/gnome/SessionManager',
+            'org.gnome.SessionManager',
+            'RegisterClient', params, null,
+            Gio.DBusCallFlags.NONE, -1, null);
+    } catch (e) {
+        log(`Error notifying gnome-session that we're ready: ${e.message}`);
+    }
+}
+
 function _handleShowWelcomeScreen() {
     const lastShownVersion = global.settings.get_string(WELCOME_DIALOG_LAST_SHOWN_VERSION);
     if (Util.GNOMEversionCompare(WELCOME_DIALOG_LAST_TOUR_CHANGE, lastShownVersion) > 0) {