Endless modem detection loop from kernel 5.1x ModemManager 1.16.6-2-20.04 Ubuntu 20.04
After Ubuntu 20.04 system update of kernel from 5.8.x to any 5.1x kernel line there is a stuck in endless ModemManager (1.16.6-2-20.04) detection/init procedure of HP lt4120 snapdragon x5 lte modem. The same version of ModemManager works flawlessly on kernel 5.8.x The hardware is correctly visible over lsusb and usb-devices on both kernels. If I boot to 5.8.x my modem is working under ModemManager, but newer 5.1x kernels shouldn't brake ModemManager functionality. The Debug log from ModemManager is attached below. No other errors or failures recorded in dmesg.
Edited by Mi Usr