Can't restore broadband connection after resume from suspend

[Mathias Hasselmann]

After resume nm-applet doesn't restore broadband connections automatically. Instead it asks for the SIM PIN[1], but after unlocking the SIM no connection is established. Connecting manually from popup results in a message box showing the following error message:

(32) Connection 'Notebook Flat' is not available on the device cdc-wdm0 at this time.

Backtrace for this dialog is:

#0 0x00007ffff70c08a0 in gtk_message_dialog_new () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#1 0x0000000000433c00 in utils_show_error_dialog (title=0x7ffff7ed5f02 "Verbindung fehlgeschlagen", text1=<optimized out>,
    text2=0xacd980 "(32) Connection 'Notebook Flat' is not available on the device cdc-wdm0 at this time.", modal=0, parent=<optimized out>) at utils.c:188
#2 0x0000000000417392 in activate_connection_cb (client=<optimized out>, active=<optimized out>, error=<optimized out>, user_data=0x791600) at applet.c:673
#3 0x00007ffff656de1a in ?? () from /usr/lib/x86_64-linux-gnu/libnm-glib.so.4
#4 0x00007ffff656f6a5 in ?? () from /usr/lib/x86_64-linux-gnu/libnm-glib.so.4
#5 0x00007ffff0e66962 in ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
#6 0x00007ffff0e69e81 in dbus_connection_dispatch () from /lib/x86_64-linux-gnu/libdbus-1.so.3
#7 0x00007ffff60cb5d5 in ?? () from /usr/lib/x86_64-linux-gnu/libdbus-glib-1.so.2
#8 0x00007ffff5347c3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9 0x00007ffff5347f20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007ffff5348242 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#11 0x00000000004132ec in main (argc=1, argv=0x7fffffffdf58) at main.c:106

Trying to debug this now. My assumption is that modem-manager publishes the modem at a new DBus path because of the unlocking and apparently nm-applet fails to pickup that new path.

[1] Although the PIN should be stored in the keyring, but let's ignore that bug for now.