Comment 0 for bug 1969241

Network issue no IPv6 using Sierra Wireless EM7421 and mbim

Description: Ubuntu Jammy Jellyfish
Release: 22.04
Linux 5.15.0-25-generic

I need to connect via GSM to Internet using IPv6.
IPv6 not present in config.
Internet connect works with IPv4 although issues seem to exist.

EXPECTATION:
Shall work properly like the EM7455 with same card in very similar machine, Ubuntu. Using the same driver=cdc_mbim

ENVIRONMENT:
SIM is working properly,
EM7421 latest firmware applied,
EM7421 capable doing IPv6 with this setup (according to spec + test with Win10);
"package" unknown, sorry.

ASSUMPTION:
Missing IPv6 is a wrong config / bug in software.
IPv6 communication can be enabled.
Some enhancement / fix can enable IPv6 communication.

details:

Actually no IPv6 available at all (IPv6 is expected to work):

3: wwan0: <BROADCAST,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000
    link/ether 6a:05:2c:26:95:58 brd ff:ff:ff:ff:ff:ff
    inet 10.34.85.36/29 brd 10.34.85.39 scope global noprefixroute wwan0

This is the Sierra Wireless GSM-Modem (working):

sudo mbimcli --device=/dev/cdc-wdm0 --query-device-caps
[/dev/cdc-wdm0] Device capabilities retrieved:
       Device type: 'remote'
    Cellular class: 'gsm'
       Voice class: 'no-voice'
         SIM class: 'removable'
        Data class: 'umts, hsdpa, hsupa, lte'
          SMS caps: 'pdu-receive, pdu-send'
         Ctrl caps: 'reg-manual'
      Max sessions: '8'
 Custom data class: 'unknown'
         Device ID: '356706140353162'
     Firmware info: 'SWI9X50C_01.14.03.00'
     Hardware info: 'EM7421'

Attempt to start modem via mbim:
pre:
sudo service network-manager stop
sudo systemctl disable ModemManager

then
Report

sudo mbim-network /dev/cdc-wdm0 start
Profile at '/etc/mbim-network.conf' not found...
Querying subscriber ready status 'mbimcli -d /dev/cdc-wdm0 --query-subscriber-ready-status --no-close'...
[/dev/cdc-wdm0] Subscriber ready status retrieved: Ready state: 'initialized' Subscriber ID: '262011905110762' SIM ICCID: '89490200001788157884' Ready info: 'none' Telephone numbers: (1) '+491604282867' [/dev/cdc-wdm0] Session not closed: TRID: '3'
Querying registration state 'mbimcli -d /dev/cdc-wdm0 --query-registration-state --no-open=3 --no-close'...
[/dev/cdc-wdm0] Registration status: Network error: 'unknown' Register state: 'home' Register mode: 'automatic' Available data classes: 'lte' Current cellular class: 'gsm' Provider ID: '26201' Provider name: 'Telekom.de' Roaming text: 'unknown' Registration flags: 'packet-service-automatic-attach' [/dev/cdc-wdm0] Session not closed: TRID: '4'
Attaching to packet service with 'mbimcli -d /dev/cdc-wdm0 --attach-packet-service --no-open=4 --no-close'...
[/dev/cdc-wdm0] Successfully attached to packet service [/dev/cdc-wdm0] Packet service status: Network error: 'unknown' Packet service state: 'attached' Available data classes: 'lte' Uplink speed: '150000000 bps' Downlink speed: '300000000 bps' [/dev/cdc-wdm0] Session not closed: TRID: '5'
Starting network with 'mbimcli -d /dev/cdc-wdm0 --connect=apn='' --no-open=5 --no-close'...
Network started successfully
Saving state at /tmp/mbim-network-state-cdc-wdm0... (TRID: 7)

status reported by ip a :
3: wwan0: <BROADCAST,MULTICAST,NOARP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether 86:a6:1f:1a:ce:30 brd ff:ff:ff:ff:ff:ff

try to bring it up:
sudo ip link set dev wwan0 up
(no error reported)

new status reported by
ip a :
3: wwan0: <BROADCAST,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000
    link/ether 86:a6:1f:1a:ce:30 brd ff:ff:ff:ff:ff:ff

(All SIM / telephony / GSM data above is real; please handle with care)

lshw reporting on USB and the like

        *-usb:2
             description: USB controller
             product: Tiger Lake-LP USB 3.2 Gen 2x1 xHCI Host Controller
             vendor: Intel Corporation
             physical id: 14
             bus info: pci@0000:00:14.0
             version: 20
             width: 64 bits
             clock: 33MHz
             capabilities: pm msi xhci bus_master cap_list
             configuration: driver=xhci_hcd latency=0
             resources: irq:155 memory:5c420000-5c42ffff
           *-usbhost:0
                product: xHCI Host Controller
                vendor: Linux 5.15.0-25-generic xhci-hcd
                physical id: 0
                bus info: usb@3
                logical name: usb3
                version: 5.15
                capabilities: usb-2.00
                configuration: driver=hub slots=12 speed=480Mbit/s
              *-usb:0
                   description: Communication device
                   product: EM7421
                   vendor: Sierra Wireless, Incorporated
                   physical id: 3
                   bus info: usb@3:3
                   version: 0.06
                   serial: 8G1202758803B121
                   capabilities: usb-2.00
                   configuration: driver=cdc_mbim maxpower=500mA speed=480Mbit/s