MC7430: ModemManager 1.14 reconnects bearer once simple-disconnected


I have a MC7430 with firmware and Telstra pri, with ModemManager 1.14, I could setup the bearer connection with the --simple-connect mmcli command, however, when I tried to disconnect with the --simple-disconnect, from syslog I saw that the MC7430 was reconnected automatically:

<30>Jan 1 00:07:22 [1608]: [modem2] state changed (connected → disconnecting)
<30>Jan 1 00:07:22 [1608]: [modem2] state changed (disconnecting → connected)

Whereas on EM7565 the --simple-disconnect could disconnect the bearer succesfully:

<30>May 1 20:11:58 [1249]: [modem1] state changed (connected → disconnecting)
<30>May 1 20:11:58 [1249]: [modem1] state changed (disconnecting → registered)

How was ModemManager auto re-connecting on MC7430? and how to debug and stop it?

Thanks a lot!

Have you compared the return of at!custom?

Thanks for your remind!

Both MC7430 and EM7565 have the following identical settings:

# /etc/scripts/modem-cmd 'AT!CUSTOM?'
response: '!CUSTOM: 
             GPSENABLE          0x01
             GPSLPM             0x01
             IPV6ENABLE         0x01
             UIM2ENABLE         0x01
             SIMLPM             0x01
             USBSERIALENABLE    0x01
             PCSCDISABLE                0x01
             CSVOICEREJECT      0x02
             SINGLEAPNSWITCH    0x01'

How about comparing the followings?


Ok, for EM7565:

# /etc/scripts/modem-cmd 'AT!ENTERCND="A710"'
response: ''
# /etc/scripts/modem-cmd 'AT!USBCOMP?'
response: 'Config Index: 1
Config Type:  3 (Generic)
Interface bitmask: 0000010D (diag,nmea,modem,rmnet0) '
# mmcli -L
    /org/freedesktop/ModemManager1/Modem/24 [Sierra Wireless, Incorporated] EM7565

And for MC7430:

# /etc/scripts/modem-cmd 'AT!ENTERCND="A710"'
response: ''
# /etc/scripts/modem-cmd 'AT!USBCOMP?'       
response: 'Config Index: 1
Config Type:  1 (Generic)
Interface bitmask: 0000050D (diag,nmea,modem,rmnet0,rmnet1) '
# mmcli -L
    /org/freedesktop/ModemManager1/Modem/0 [Sierra Wireless, Incorporated] MC7430

Looks like the the only difference is that MC7430 has extra rmnet1(wwan1) than EM7565.

Any improvememt to disable rmnet1 in mc7430?

You might also see this:

1 Like

Thanks again!

Well, I have very positive findings following your advice to disable rmnet1 configurations. My findings are:

  1. With rmnet0 and rmnet1 configurations both enabled, wwan0 and wwan1 are available
  2. The wwan1 interface is more likely used than wwan0 by linux kernel, to obtain IP address from the bearer
  3. With wwan1 interface, after --simple-disconnect, the ModemManager auto re-connects the cellmodem
  4. However, if the remnet1 is configured off, only rmnet0 and wwan0 interfaces are available
  5. With wwan0 interface, after --simple-disconnect, the ModemManager will NOT auto re-connect the cellmodem anymore, the cellmodem’s state changes through connected → disconnecting → registered

OK, my follow-up questions are:

  1. On MC73xx and MC74xx, when both rmnet0/1 and wwan0/1 interfaces are available, what are factors determining which wwanX interface is used? Sometimes I noticed that the kernel seems to ping-pong among them after cellmodem resets and bearer re-connects

  2. On MC7430, why with rmnet1/wwan1 the ModemManager would auto re-connect the cellmodem after --simple-disconnect was handled properly? why it stops doing so with the rmnet0/wwan0 interface?

Thanks again! Much appreciated!


Here says it might be related to network manager

Thanks again!

I am using an embedded Linux distribution without network manager, just ModemManager and libqmi sort of stuff.

I am wondering how I could keep debugging ModemManager auto re-connection behaviour on rmnet1/wwan1. If rmnet1 is disabled on MC7430, or not existing in the first place such as on EM7565, such behaviour doesn’t seem to exist.


why do you keep two rmnet interface?

Good point!

The ModemManager’s auto re-connection upon --simple-disconnect can be avoided by disabling rmnet1/wwan1. I will fall back on that if needed. The real question goes to why ModemManager auto re-connects on rmnet1 but not on rmnet0.


no idea, you might need to see any configuration file for modem manager or network manager