EM 7455 Disconnecting under ubuntu 17.10

Hi,

I have a linux box running ubuntu 17.10. My wwan card is lenovo em 7455, which is currently running generic firmware 9999999_9904609_SWI9X30C_02.24.03.00_00_GENERIC_002.021_000 (I also tried 9999999_9904609_SWI9X30C_02.20.03.00_00_GENERIC_002.017_000 and it’s the same) with a sprint sim card with unlimited data plan. I have to use generic firmware if I use sprint firmware it will disconnect after a few minutes and will not reconnect even if I checked auto-reconnect in network-manager.

The symptom is my wwan keeps disconnecting every a few seconds, in network-manager I’m able to set it to auto reconnect but it will disconnect non-stop. Using “journalctl -xf | grep state” I can see the log

Aug 26 11:33:51 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761631.6229] device (cdc-wdm2): state change: ip-config -> ip-check (reason 'none') [70 80 0]
Aug 26 11:33:51 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761631.6262] device (cdc-wdm2): state change: ip-check -> secondaries (reason 'none') [80 90 0]
Aug 26 11:33:51 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761631.6271] device (cdc-wdm2): state change: secondaries -> activated (reason 'none') [90 100 0]
Aug 26 11:33:59 qwertyegg-STCK1A8LFC ModemManager[798]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connected -> registered)
Aug 26 11:33:59 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761639.7887] (cdc-wdm2): modem state changed, 'connected' --> 'registered' (reason: user-requested)
Aug 26 11:33:59 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761639.7889] device (cdc-wdm2): state change: activated -> failed (reason 'modem-no-carrier') [100 120 25]
Aug 26 11:33:59 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761639.8516] device (cdc-wdm2): state change: failed -> disconnected (reason 'none') [120 30 0]
Aug 26 11:33:59 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761639.8738] device (cdc-wdm2): state change: disconnected -> prepare (reason 'none') [30 40 0]
Aug 26 11:33:59 qwertyegg-STCK1A8LFC ModemManager[798]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (registered -> connecting)
Aug 26 11:33:59 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761639.9226] (cdc-wdm2): modem state changed, 'registered' --> 'connecting' (reason: user-requested)
Aug 26 11:34:00 qwertyegg-STCK1A8LFC ModemManager[798]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connecting -> connected)
Aug 26 11:34:00 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761640.8453] (cdc-wdm2): modem state changed, 'connecting' --> 'connected' (reason: user-requested)
Aug 26 11:34:00 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761640.8549] device (cdc-wdm2): state change: prepare -> config (reason 'none') [40 50 0]
Aug 26 11:34:00 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761640.8560] device (cdc-wdm2): state change: config -> ip-config (reason 'none') [50 70 0]
Aug 26 11:34:00 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761640.8710] device (cdc-wdm2): state change: ip-config -> ip-check (reason 'none') [70 80 0]
Aug 26 11:34:00 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761640.8752] device (cdc-wdm2): state change: ip-check -> secondaries (reason 'none') [80 90 0]
Aug 26 11:34:00 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761640.8824] device (cdc-wdm2): state change: secondaries -> activated (reason 'none') [90 100 0]
Aug 26 11:34:09 qwertyegg-STCK1A8LFC ModemManager[798]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connected -> registered)
Aug 26 11:34:09 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761649.4863] (cdc-wdm2): modem state changed, 'connected' --> 'registered' (reason: user-requested)
Aug 26 11:34:09 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761649.4865] device (cdc-wdm2): state change: activated -> failed (reason 'modem-no-carrier') [100 120 25]
Aug 26 11:34:09 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761649.5544] device (cdc-wdm2): state change: failed -> disconnected (reason '

It seems like this line is the problem

Aug 26 11:33:59 qwertyegg-STCK1A8LFC NetworkManager[765]: <info>  [1503761639.7889] device (cdc-wdm2): state change: activated -> failed (reason 'modem-no-carrier') [100 120 25]

I tried to do some search myself but didn’t see much related topics. I appreciate anyone’s help.

Hello,

Have you installed Sierra QMI drivers ?. I’ve EM7455 installed on DELL E7270 running Ubuntu 17.04 as well installed with latest Sierra QMI drivers and looks like so far no issues either setup using MBIM or QMI.

Thanks for reply zainol69, I’m will only be able to test QMI drivers under linux during week days I’ll try that and report back.

I am having similar problem. I plugged my em7455 modem into khadas vim3 pro. It appears in the device details but I couldn’t run it because I couldn’t install the driver. I am using Ubuntu 20.04 arm. I looked at the documents but didn’t understand anything.