ModemManager and Quectel RM520N-GL

[Aleksander Morgado]

On Fri, Mar 3, 2023 at 12:45 PM Patrick Kosiol <patrick.kosiol at gmx.de> wrote:
>
> Hi,
>
> It appears my ModemManager cannot initialize the Quectel RM520N-GL modem with the messages
> <dbg> [000001775.270989] [modem0] couldn't start parent initialization: Couldn't open ports during modem initialization: Couldn't get primary port
> <wrn> [000001775.275716] [modem0] modem couldn't be initialized: Failed to load current capabilities: Couldn't peek client for service ‘nas'
>
> Perhaps someone has an idea what the reason might be? That would help me very much.
>

>From the debug log:

<dbg> [000001775.005392] [/dev/cdc-wdm0] received generic response
(translated)...
<<<<<< QMUX:
<<<<<<   length  = 18
<<<<<<   flags   = 0x80
<<<<<<   service = "ctl"
<<<<<<   client  = 0
<<<<<< QMI:
<<<<<<   flags       = "response"
<<<<<<   transaction = 6
<<<<<<   tlv_length  = 7
<<<<<<   message     = "Allocate CID" (0x0022)
<<<<<< TLV:
<<<<<<   type       = "Result" (0x02)
<<<<<<   length     = 4
<<<<<<   value      = 01:00:05:00
<<<<<<   translated = FAILURE: ClientIdsExhausted

<dbg> [000001775.006317] [modem0] couldn't allocate client for service
'nas': Couldn't create client for service 'nas': QMI protocol error
(5): 'ClientIdsExhausted'

Do you have any other process attempting to use QMI in the system?
E.g. are you running some qmicli commands or something at the same
time?

The error above shows how a NAS client allocation fails with
ClientIdsExhausted, which indicates that there are unreleased NAS
clients around. ModemManager takes care of allocating clients and
releasing them properly when they're no longer used.

If no other processes are running QMI operations, could it be that MM
is not being cleanly shutdown at some point and then restarted?

-- 
Aleksander