Hello All, We am seeing a strange issue where Modem instance reconnects automatically once in a while, modem used in EM7455. This happens after some time of succesful data connection and the once the issue occurs network is disrupted for 30-45 seconds. This is very random and some times happens quite often like every 1 hour or so. >From the debug logs I can see there is USB disconnect and qcdm reports >"unexpected port hangup" . I tried searching modemforums and issues in gitlab<https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/?search=forced%20to%20close%20port&sort=created_date&state=opened&first_page_size=20>, but didn't find any one reporting this kind of behavior for EM7455, it would be of great help if anyone can throw some light on this failure.
Logs: >From logs: 2023-02-03T16:56:13.564 INFO kern kernel:[16332.259560] usb 1-1.3: USB disconnect, device number 5 2023-02-03T16:56:13.044 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB0/qcdm] unexpected port hangup! 2023-02-03T16:56:13.044 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB0/qcdm] forced to close port 2023-02-03T16:56:13.044 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB0/qcdm] device open count is 0 (close) 2023-02-03T16:56:13.044 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB0/qcdm] closing serial port 2023-02-03T16:56:13.044 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB0/qcdm] serial port closed 2023-02-03T16:56:13.565 INFO kern kernel:[16332.261131] qcserial ttyUSB0: Qualcomm USB modem converter now disconnected from ttyUSB0 2023-02-03T16:56:13.566 INFO kern kernel:[16332.261629] qcserial 1-1.3:1.0: device disconnected 2023-02-03T16:56:13.567 INFO kern kernel:[16332.262427] qcserial ttyUSB1: Qualcomm USB modem converter now disconnected from ttyUSB1 2023-02-03T16:56:13.567 INFO kern kernel:[16332.262472] qcserial 1-1.3:1.2: device disconnected 2023-02-03T16:56:13.047 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB2/at] unexpected port hangup! 2023-02-03T16:56:13.047 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB2/at] forced to close port 2023-02-03T16:56:13.047 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB2/at] device open count is 0 (close) 2023-02-03T16:56:13.047 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB2/at] closing serial port... 2023-02-03T16:56:13.047 DEBUG daemon ModemManager[5106]: <debug> [modem0/ttyUSB2/at] serial port closed 2023-02-03T16:56:13.569 INFO kern kernel:[16332.264374] qcserial ttyUSB2: Qualcomm USB modem converter now disconnected from ttyUSB2 2023-02-03T16:56:13.569 INFO kern kernel:[16332.264424] qcserial 1-1.3:1.3: device disconnected 2023-02-03T16:56:13.572 INFO kern kernel:[16332.267600] qmi_wwan 1-1.3:1.8 wwan0: unregister 'qmi_wwan' usb-0000:00:16.0-1.3, WWAN/QMI device 2023-02-03T16:56:13.053 NOTICE daemon netifd: Network device 'wwan0' link is down Versions used libqmi: 1.28.6-1 libmbim: 1.24.8-1 modemmanager: 1.16.6.1 openwrt: 19.07 based solution. Carrier : Vodafone EM7455 firmware used: "SWI9X30C_02.24.03.00 r6978 CARMD-EV-FRMWR2 2017/03/02 13:36:45 response: '!IMPREF: ^M preferred fw version: 02.24.03.00^M preferred carrier name: VODAFONE^M preferred config name: VODAFONE_001.001_000^M current fw version: 02.24.03.00^M current carrier name: VODAFONE^M current config name: VODAFONE_001.001_000' Thanks, Pradeep G
