a bug?

Dan Williams dcbw at redhat.com
Wed Apr 29 14:19:22 PDT 2015

On Wed, 2015-04-29 at 22:49 +0200, Jean-Pierre.Eckmann at unige.ch wrote:
> On Ubuntu 14.04
> mmcli -L says 8after many sleeps)
> /org/freedesktop/ModemManager1/Modem/57 [Generic] MBIM [1199:A001]
> but
> tcsh>mmcli --pin=1213 --sim=57
> error: couldn't find sim at '/org/freedesktop/ModemManager1/SIM/57'
> where actually
> mmcli --pin=1213 --sim=53
> successfully sent PIN code to the SIM
> what is wrong here?

I think ModemManager is not compiled with suspend/resume support, and
that the version of MM in 14.04 is probably too old to have that support
in the code.

What's going on is that when the machine goes to sleep, ModemManager has
no idea about this, and because of that it holds the control port open
over the suspend/resume.  But since the modem's other ports are not held
open by MM, they can disappear when power is cut to the modem and it
disconnects from the USB bus.

Then when a resume happens, the modem comes back and the control port is
brought back up again, but the other ports are re-created by the kernel
and MM goes through the normal probing cycle, which creates a new modem
object (57) in addition to the old one, but since this new one doesn't
have control port it's useless.

It looks like the suspend/resume support is only present on git master;
I think we should probably backport it to MM 1.4 too.  Aleksander, does
that sound reasonable?


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