Если модем подключен, то система просто зависает через неопределенное время, но не много, минут через 5 максимум. Зависает сразу, как только подключаешь интернет. Далее привожу фрагмент syslog.
Oct 24 16:14:45 aleksei-Home-PC systemd-udevd[258]: error: /dev/sdc: No medium found
Oct 24 16:14:45 aleksei-Home-PC usb_modeswitch: switch device 12d1:1446 on 004/003
Oct 24 16:14:45 aleksei-Home-PC systemd-udevd[1645]: Failed to apply ACL on /dev/sr0: No such file or directory
Oct 24 16:14:45 aleksei-Home-PC kernel: [ 105.580857] usb 4-1: USB disconnect, device number 3
Oct 24 16:14:45 aleksei-Home-PC kernel: [ 105.583990] scsi 13:0:0:0: rejecting I/O to offline device
Oct 24 16:14:45 aleksei-Home-PC kernel: [ 105.583997] scsi 13:0:0:0: killing request
Oct 24 16:14:45 aleksei-Home-PC systemd-udevd[258]: error: /dev/sdc: No such file or directory
Oct 24 16:14:45 aleksei-Home-PC systemd-udevd[1636]: inotify_add_watch(7, /dev/sdc, 10) failed: No such file or directory
Oct 24 16:14:45 aleksei-Home-PC systemd-udevd[258]: error opening USB device 'descriptors' file
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 111.928796] usb 4-1: new full-speed USB device number 4 using ohci-pci
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.155667] usb 4-1: New USB device found, idVendor=12d1, idProduct=1003
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.155673] usb 4-1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.155675] usb 4-1: Product: HUAWEI Mobile
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.155677] usb 4-1: Manufacturer: HUAWEI Technology
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.163740] usb-storage 4-1:1.0: USB Mass Storage device detected
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.164224] option 4-1:1.0: GSM modem (1-port) converter detected
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.164324] usb 4-1: GSM modem (1-port) converter now attached to ttyUSB0
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.164411] usb-storage 4-1:1.1: USB Mass Storage device detected
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.164490] option 4-1:1.1: GSM modem (1-port) converter detected
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.164558] usb 4-1: GSM modem (1-port) converter now attached to ttyUSB2
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.164651] usb-storage 4-1:1.2: USB Mass Storage device detected
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.166678] scsi host16: usb-storage 4-1:1.2
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.166813] usb-storage 4-1:1.3: USB Mass Storage device detected
Oct 24 16:14:51 aleksei-Home-PC kernel: [ 112.169661] scsi host17: usb-storage 4-1:1.3
Oct 24 16:14:51 aleksei-Home-PC mtp-probe: checking bus 4, device 4: "/sys/devices/pci0000:00/0000:00:04.0/usb4/4-1"
Oct 24 16:14:51 aleksei-Home-PC mtp-probe: bus: 4, device: 4 was not an MTP device
Oct 24 16:14:51 aleksei-Home-PC ModemManager[574]: <warn> (ttyUSB2): port attributes not fully set
Oct 24 16:14:52 aleksei-Home-PC usb_modeswitch_dispatcher[1659]: message repeated 4 times: [ Could not read attribute: No such file or directory]
Oct 24 16:14:52 aleksei-Home-PC usb_modeswitch[1659]: usb_modeswitch: switched to 12d1:1003 on 4/4
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.173013] scsi 16:0:0:0: CD-ROM HUAWEI Mass Storage 2.31 PQ: 0 ANSI: 2
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.177026] scsi 17:0:0:0: Direct-Access HUAWEI MMC Storage 2.31 PQ: 0 ANSI: 2
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.201965] sr 16:0:0:0: [sr0] scsi-1 drive
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.202228] sr 16:0:0:0: Attached scsi CD-ROM sr0
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.202418] sr 16:0:0:0: Attached scsi generic sg2 type 5
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.202812] sd 17:0:0:0: Attached scsi generic sg3 type 0
Oct 24 16:14:52 aleksei-Home-PC ModemManager[574]: <warn> (ttyUSB0): port attributes not fully set
Oct 24 16:14:52 aleksei-Home-PC kernel: [ 113.224958] sd 17:0:0:0: [sdc] Attached SCSI removable disk
Oct 24 16:14:53 aleksei-Home-PC usb_modeswitch[1659]: usb_modeswitch: add device ID 12d1:1003 to driver option
Oct 24 16:14:53 aleksei-Home-PC usb_modeswitch[1659]: usb_modeswitch: please report the device ID to the Linux USB developers!
Oct 24 16:14:53 aleksei-Home-PC usb_modeswitch_dispatcher[1659]: Unable to open bind list file: No such file or directory
Oct 24 16:14:53 aleksei-Home-PC systemd-udevd[258]: error: /dev/sdc: No medium found
Oct 24 16:14:55 aleksei-Home-PC ModemManager[574]: <warn> (ttyUSB2): port attributes not fully set
Oct 24 16:14:55 aleksei-Home-PC ModemManager[574]: <info> Creating modem with plugin 'Huawei' and '2' ports
Oct 24 16:14:55 aleksei-Home-PC ModemManager[574]: <warn> (ttyUSB2): port attributes not fully set
Oct 24 16:14:55 aleksei-Home-PC ModemManager[574]: <info> Modem for device at '/sys/devices/pci0000:00/0000:00:04.0/usb4/4-1' successfully created
Oct 24 16:14:56 aleksei-Home-PC ModemManager[574]: Error while checking ^SYSCFGEX format: Unknown error
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem: state changed (unknown -> disabled)
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <warn> (ttyUSB2): failed to look up interface index
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): modem state changed, 'disabled' --> 'enabling' (reason: user preference)
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): new Broadband device (driver: 'option1' ifindex: 0)
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): exported as /org/freedesktop/NetworkManager/Devices/3
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem /org/freedesktop/ModemManager1/Modem/1: state changed (disabled -> enabling)
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <warn> (ttyUSB2): port attributes not fully set
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): preparing device
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): modem state 'enabling'
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): device state change: unavailable -> disconnected (reason 'none') [20 30 0]
Oct 24 16:15:00 aleksei-Home-PC systemd[1]: Started USB_ModeSwitch.
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem /org/freedesktop/ModemManager1/Modem/1: 3GPP Registration state changed (unknown -> registering)
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem /org/freedesktop/ModemManager1/Modem/1: 3GPP Registration state changed (registering -> home)
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem /org/freedesktop/ModemManager1/Modem/1: 3GPP location updated (MCC: '0', MNC: '0', Location area code: 'C7EF', Cell ID: '3846')
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem /org/freedesktop/ModemManager1/Modem/1: 3GPP location updated (MCC: '250', MNC: '99', Location area code: 'C7EF', Cell ID: '3846')
Oct 24 16:15:00 aleksei-Home-PC ModemManager[574]: <info> Modem /org/freedesktop/ModemManager1/Modem/1: state changed (enabling -> registered)
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): modem state changed, 'enabling' --> 'registered' (reason: user-requested)
Oct 24 16:15:00 aleksei-Home-PC NetworkManager[578]: <info> (ttyUSB2): modem re-registered; re-checking autoconnect
Oct 24 16:15:02 aleksei-Home-PC org.freedesktop.Notifications[1063]: ** (notify-osd:1422): WARNING **: dnd_is_screensaver_active(): Got error "Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken."
Oct 24 16:15:08 aleksei-Home-PC kernel: [ 128.554262] nouveau E[ DRM] GPU lockup - switching to software fbcon
Oct 24 16:15:27 aleksei-Home-PC systemd[1]: Stopping User Manager for UID 112...
