This is not a NetworkManager problem. It is also reported by me in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1950385 and it is probably kernel bug. The problem is described by ModemManager's developer in our discussion: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/463#note_1157289 as a broken USB communication. According to diagnosis from kernel 5.1x the qmi_wwan module resets modem firmware in endless loop: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/463#note_1157919 although it was worked flawlessly earlier in kernel 5.8.x
The workaround is to use udev script for a modem to switch it to the MBIM mode which works ok under ModemManager & NetworkManager. Reboot. Recreate connection profile for modem in Network Manager Mobile Broadband Settings for your GSM Network Provider to make it binded with new MBiM devid config. Tested on kernels 5.8, 5,11, 5.13. Place the attached udev script file in: /etc/udev/rules.d instead of any old one. It uses usb_modeswitch to do the "magic" correctly. ** Attachment removed: "Udev script for switching modem" https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1574582/+attachment/5541060/+files/99-hp-lt4120.rules ** Attachment added: "udev script for modem" https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1574582/+attachment/5541062/+files/99-hp-lt4120.rules -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1574582 Title: HP lt4120 Snapdragon X5 LTE USB modem not recognized by network- manager Status in network-manager package in Ubuntu: Confirmed Bug description: USB modem not recognized by network-manager. Modem information in attached ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: network-manager 1.1.93-0ubuntu4 ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6 Uname: Linux 4.4.0-21-generic x86_64 ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 CasperVersion: 1.376 Date: Mon Apr 25 11:14:04 2016 IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback IpRoute: default via 10.106.36.1 dev wlp2s0 proto static metric 600 1.1.1.1 via 10.106.36.1 dev wlp2s0 proto dhcp metric 600 10.106.36.0/22 dev wlp2s0 proto kernel scope link src 10.106.39.123 metric 600 169.254.0.0/16 dev wlp2s0 scope link metric 1000 LiveMediaBuild: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=true ProcEnviron: TERM=xterm-256color PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: network-manager UpgradeStatus: No upgrade log present (probably fresh install) nmcli-dev: DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH wlp2s0 wifi connected /org/freedesktop/NetworkManager/Devices/1 IQORAMS_REPAIR 3b1e13ff-f9c9-4a49-a576-465bc2713e21 /org/freedesktop/NetworkManager/ActiveConnection/1 enxb2e41f35ffe1 ethernet disconnected /org/freedesktop/NetworkManager/Devices/2 -- -- -- enp0s31f6 ethernet unavailable /org/freedesktop/NetworkManager/Devices/3 -- -- -- lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/0 -- -- -- nmcli-nm: Error: command ['nmcli', '-f', 'all', 'nm'] failed with exit code 2: Error: Object 'nm' is unknown, try 'nmcli help'. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1574582/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
