Can't connect using ModemManager when modem is in QMI mode

Bushman, Jeff jbushman at
Wed Dec 1 18:34:21 UTC 2021

I have attached the modem manager debug logs. Search for "simple connect". One odd thing I noticed was a log message about "reseting expected kernel data format to 802.3 in data interface 'wwan0'" which is not correct. The interface has always worked as raw-ip.

Here is the list of commands I sent:

  436  mmcli -L
  437  mmcli -m 0
  438  mmcli -m 0 --enable
  439  mmcli -m 0 --simple-connect='apn=broadband'
  441  mmcli -m 0 --3gpp-profile-manager-list
  442  mmcli -m 0
  443  mmcli -b 0
  444  mmcli -b 1
  445  mmcli -m 0 --reset
  446  mmcli -L
  448  mmcli -L
  449  mmcli -m 1
  450  mmcli -m 1 --enable
  451  mmcli -m 1
  452  mmcli -b 2
  454  mmcli -m 1 --bearer 2 --connect
  455  mmcli -m 1 --diable
  456  mmcli -m 1 --disable
  457  mmcli -L
  458  mmcli -m 1
  459  mmcli -m 1 --simple-status
  461  mmcli -m 1 --simple-connect='apn=broadband'
  462  mmcli -m 1
  463  mmcli -b 3
  464  mmcli -b 4

-----Original Message-----
From: Aleksander Morgado <aleksander at> 
Sent: Wednesday, December 1, 2021 2:15 AM
To: Bushman, Jeff <jbushman at>
Cc: modemmanager-devel at
Subject: [**EXTERNAL**] Re: Can't connect using ModemManager when modem is in QMI mode

Hey Jeff,

> I'm running a Sierra Wireless MC7455 modem with SWI9X30C_02.32.11.00 r8042 CARMD-EV-FRMWR2 firmware. Using ModemManager 1.18.2 on Ubuntu 20.04.
> I can get the modem to connect using mmcli -m 0 --simple-connect=. when the modem is in MBIM mode.
> I can get the modem to connect using qmicli and qmi-network when the modem is in QMI mode.
> But when I use mmcli with ModemManager, --simple-connect fails with
>     error: couldn't connect the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.Cancelled: operation cancelled'

Oh, that is very strange.

> What is strange is that the modem seems to create a default bearer channel when it is enabled. Using simple-connect seems to create a second bearer channel which is rejected. But using -connect on the default bearer channel also fails.

The default bearer when enabled is the "initial EPS default bearer".
In ModemManager, this is an informative bearer object exclusively, you cannot use it to trigger a connection. When simple connect creates the new bearer, that's the one that should end up connected.

> Using simple connect results in two bearers.
> root at de-01:~# mmcli -m 1 --simple-connect='apn=broadband'
> error: couldn't connect the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.Cancelled: operation cancelled'

This is what we need to understand. Could you gather MM daemon debug logs while you attempt this simple-connect operation?;!!OSsGDw!fV-_YRbufvcelVcBcO6H9MctlLi6mh-ziJtAiZybF9Oa6JEUZxuRyetlFPigVA$ [modemmanager[.]org]

Aleksander;!!OSsGDw!fV-_YRbufvcelVcBcO6H9MctlLi6mh-ziJtAiZybF9Oa6JEUZxuRyevjzE6OBQ$ [aleksander[.]es]
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