nm-applet cannot communicate with ModemManager on serveral Hardware

[Aleksander Morgado]

On Sat, Aug 22, 2015 at 2:14 PM, Harald Jung <harald.jung at ecos.de> wrote:
> we are running a selfmade Distro, which is gentoo based.
> Modemmanager is started by Networkmanager via dbus.

Ideally ModemManager shouldn't be autostarted by NetworkManager. We
explicitly avoid this in recent releases of NM when using systemd;
where we rely on MM being a systemd service itself (i.e. we just watch
the MM name in the bus, never request to auto-start it).

> Here is the order of the services, started by our runlevel script:
> syslogd
> klogd
> udev
> dbus
> networkmanager
> 8 different networkservices
> X
> xfce (which starts nm-applet via autostart)
>
> The thing i am wondering about is that it works on most notebooks, but not
> on all, so it is related to the hardware it runs from


The issue you're experiencing, though, is a bit unrelated I believe.
This looks like a race within nm-applet, where the creation of the
MMManager object in the NMApplet gets finished after something has
already requested to use the MMManager. Or something like that.

https://git.gnome.org/browse/network-manager-applet/tree/src/applet.c

The following warning is because the "mm1" instance (the MMManager
object) doesn't exist.
(nm-applet:2371): nm-applet-WARNING **: Cannot grab information for
modem at /org/freedesktop/ModemManager1/Modem/0: No ModemManager
support

But this object's creation is explicitly requested when the NMApplet
is created. And note that the MMManager object will be successfully
created even if MM is not running!

I'd suggest you fill a bug in GNOME's bugzilla for the applet component.

-- 
Aleksander
https://aleksander.es