libqmi compatible with Quectel RM520N-GL (quectel driver qmi_wwan_q, or is standard driver needed)? Multiple parallel connections...

[Martin Maurer]

Hello,

sorry, if this is a beginner question:

I want to use the Quectel RM520N-GL. I want to build up multiple 
IPv4/IPv6 connections.

First I used the driver which is delivered by Linux 6.1.21 (on a 
Raspberry Pi 4, 64 bit).

I was able to test some basic things with qmicl like

$ sudo qmicli --device=/dev/cdc-wdm0 --device-open-proxy --dms-get-model
[/dev/cdc-wdm0] Device model retrieved:
         Model: 'RM520N-GL'
$

With first steps I was not able to build up a connection (but this could 
be due to misconfiguration in my environment).

I thought I try Quectel delivered driver next.

I compiled/installed it, used their Connection Manager quectel-CM and 
after some changes (especially dhcp), I was able to build up a 
connection and ping remote side via IPv4.

So now, back to original step, try libqmi (proprietary quectel driver 
still in use):

$ sudo qmicli --device=/dev/cdc-wdm0 --device-open-qmi 
--wds-get-channel-rates
[15 Aug 2023, 16:02:21] -Warning ** [/dev/cdc-wdm0] couldn't detect 
transport type of port: unexpected driver detected: qmi_wwan_q
[15 Aug 2023, 16:02:21] -Warning ** [/dev/cdc-wdm0] requested QMI mode 
but unexpected transport type found
error: couldn't create client for the 'wds' service: CID allocation 
failed in the CTL client: Transaction timed out
$ sudo qmicli --device=/dev/cdc-wdm0 --device-open-proxy 
--wds-get-channel-rates
[15 Aug 2023, 16:02:58] -Warning ** [/dev/cdc-wdm0] couldn't detect 
transport type of port: unexpected driver detected: qmi_wwan_q
error: couldn't open the QmiDevice: Cannot automatically select QMI/MBIM 
mode
$

Ok, now I am a bit lost, which way to go:

Can qmicl be used together with quectel driver and I just need to ignore 
warnings and change some settings?

Or must I deinstall quectel proprietary driver to get libqmi working again?

Does libqmi and standard qmi wwan driver support multiple parallel 
connections? As far as I have seen, libqmi seems to supports it.

Do I need to tell the quectel modem somehow to enable more than one 
connection? Or some parameter/setting for standard driver needed?

For my info: Shall I see more than one /dev/cdc-wdm? Or all done via 
this single entry point/device?

Many thanks for some hints!

Best regards,

Martin