Ubuntu 22.04 LTS / Qualcomm Snapdragon X55 5G / NetworkManager config

I am having problems getting the Network Manager in Ubuntu 22.04 LTS to correctly turn on the onboard Qualcomm Snapdragon X55 5G modem. If I try it seems NM tries to configure the connection, but never turn on the hardware needed.

If I do a

$> sudo qmicli -p -d /dev/wwan0mbim0 --device-open-auto --dms-foxconn-set-fcc-authentication=0

And then enable with

$> sudo mmcli -m 0 --enable

I am able to turn the modem on. If I then proceed to enter the APN data I get as far as being able to ping Google DNS servers at 8.8.8.8.

I then tried to set the DNS:

$> nmcli connection modify Oister\ Bredbaand ipv4.dns "8.8.8.8,8.8.4.4" 

However I am not able to do an actual host lookup on anything - I think the fact I dared turn on the modem by hand has the whole systemd very upset.

After fiddeling some more with this i removed the above manual DNS config and set

$> sudo nmcli connection modify Oister\ Bredbaand ipv4.method "auto"

and

$> sudo nmcli connection modify Oister\ Bredbaand ipv6.method "DHCP"

I now have mobile internet!

However I still have to start the connection - see the icon flickering in the top bar as it tries to configure a connection on hardware that is not started - and then start it by hand as per qmcli.

This smells like a network manager bug.

  -----------------------------------
  General  |                    path: /org/freedesktop/ModemManager1/Modem/0
           |               device id: 7099c435a92638d780ea65442842224ca7bfcf8c
  -----------------------------------
  Hardware |            manufacturer: foxconn
           |                   model: Qualcomm Snapdragon X55 5G
           |       firmware revision: T99W175.F0.0.0.5.7.GC.004
           |                          076
           |          carrier config: GCF
           | carrier config revision: 0A000804
           |            h/w revision: Qualcomm Snapdragon X55 5G
           |               supported: gsm-umts, lte, 5gnr
           |                 current: gsm-umts, lte, 5gnr
           |            equipment id: 015805000279146
  -----------------------------------
  System   |                  device: /sys/devices/pci0000:00/0000:00:1c.0/0000:08:00.0
           |                 drivers: mhi-pci-generic
           |                  plugin: foxconn
           |            primary port: wwan0mbim0
           |                   ports: wwan0 (net), wwan0at0 (at), wwan0mbim0 (mbim), 
           |                          wwan0qcdm0 (qcdm)
  -----------------------------------
  Status   |          unlock retries: sim-pin2 (3)
           |                   state: disabled
           |             power state: low
           |          signal quality: 0% (cached)
  -----------------------------------
  Modes    |               supported: allowed: 3g; preferred: none
           |                          allowed: 4g; preferred: none
           |                          allowed: 3g, 4g; preferred: 4g
           |                          allowed: 3g, 4g; preferred: 3g
           |                          allowed: 5g; preferred: none
           |                          allowed: 4g, 5g; preferred: 5g
           |                          allowed: 4g, 5g; preferred: 4g
           |                          allowed: 3g, 5g; preferred: 5g
           |                          allowed: 3g, 5g; preferred: 3g
           |                          allowed: 3g, 4g, 5g; preferred: 5g
           |                          allowed: 3g, 4g, 5g; preferred: 4g
           |                          allowed: 3g, 4g, 5g; preferred: 3g
           |                 current: allowed: 3g, 4g; preferred: 4g
  -----------------------------------
  Bands    |               supported: utran-1, utran-3, utran-4, utran-6, utran-5, utran-8, 
           |                          utran-9, utran-2, eutran-1, eutran-2, eutran-3, eutran-4, eutran-5, 
           |                          eutran-7, eutran-8, eutran-12, eutran-13, eutran-14, eutran-17, 
           |                          eutran-18, eutran-19, eutran-20, eutran-25, eutran-26, eutran-28, 
           |                          eutran-29, eutran-30, eutran-32, eutran-34, eutran-38, eutran-39, 
           |                          eutran-40, eutran-41, eutran-42, eutran-46, eutran-48, eutran-66, 
           |                          eutran-71, utran-19
           |                 current: utran-1, utran-4, utran-6, utran-5, utran-8, utran-9, 
           |                          utran-2, eutran-1, eutran-2, eutran-3, eutran-4, eutran-5, eutran-7, 
           |                          eutran-8, eutran-12, eutran-13, eutran-14, eutran-17, eutran-18, 
           |                          eutran-19, eutran-20, eutran-25, eutran-26, eutran-28, eutran-29, 
           |                          eutran-30, eutran-32, eutran-34, eutran-38, eutran-39, eutran-40, 
           |                          eutran-41, eutran-42, eutran-46, eutran-48, eutran-66, eutran-71, 
           |                          utran-19
  -----------------------------------
  IP       |               supported: ipv4, ipv6, ipv4v6
  -----------------------------------
  3GPP     |                    imei: 015805000279146
           |           enabled locks: fixed-dialing
  -----------------------------------
  3GPP EPS |    ue mode of operation: csps-2
           |  initial bearer ip type: ipv4v6
  -----------------------------------
  SIM      |        primary sim path: /org/freedesktop/ModemManager1/SIM/0
           |          sim slot paths: slot 1: /org/freedesktop/ModemManager1/SIM/0 (active)
           |                          slot 2: /org/freedesktop/ModemManager1/SIM/1

This worked better in 21.10 where the modem could be turned on and configured by NetworkManager, but it did not survive a hibernation / lid close.