why is the `-p` flag required?

[AndySchroder]

On

lpac-libmbim-wrapper/wrapper.py

Line 23 in 4641f27

output_bytes = subprocess.check_output(["mbimcli", "-p", "-d", DEV] + command.split(),

we have a -p flag that is passed to mbimcli. What is this for? It's not working for me with that. Getting the following:

$ sudo mbimcli -p -d /dev/cdc-wdm0 --ms-set-uicc-open-channel="application-id=a0000005591010ffffffff8900000100"
error: operation failed: MBIM protocol error: NotOpened
$

However, if I remove -p, I get:

$ sudo mbimcli -d /dev/cdc-wdm0 --ms-set-uicc-open-channel="application-id=a0000005591010ffffffff8900000100"
Succesfully retrieved open channel info:
	  status: 144
	 channel: 3
	response: 6F:1F:84:10:A0:00:00:05:59:10:10:FF:FF:FF:FF:89:00:00:01:00:A5:04:9F:65:01:FF:E0:05:82:03:02:02:02
$

[stich86]

-p is for Proxy call, otherwise each time you got error of not open channel

[AndySchroder]

okay, but I'm getting an error with it that says NotOpened

[stich86]

okay, but I'm getting an error with it that says NotOpened

Which modem and libmbim version? I've tested it under Ubuntu 23.10 and OpenWrt SNAPSHOT without any issue using proxy mode

[AndySchroder]

$ mbimcli -V
mbimcli 1.28.0
Copyright (C) 2013-2021 Aleksander Morgado
License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl-2.0.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

$

[AndySchroder]

$ cat /etc/issue
Ubuntu 22.04.4 LTS \n \l

[AndySchroder]

  Hardware |            manufacturer: Quectel
           |                   model: EM120R-GL

[AndySchroder]

$ uname -a
Linux rd 5.15.0-1053-raspi #56-Ubuntu SMP PREEMPT Mon Apr 15 18:50:10 UTC 2024 aarch64 aarch64 aarch64 GNU/Linux

[AndySchroder]

I can use lpac in AT mode fine by the way. That is undesirable though because ModemManager locks the tty up and I have to stop the ModemManager service to use lpac every time, which also disconnects my internet connection. I'm hoping MBIM mode won't have that problem.

[AndySchroder]

Where is the application-id coming from? Is that something that lpac makes up?

[stich86]

Yes all application ids are generated by LPAC, wrapper just get it from stdin and pass to mbimcli in a correct way

[AndySchroder]

Is ModemManager supposed to be started or stopped when using this wrapper?

[stich86]

If it's using MBIM port, I think it's better to close it

[AndySchroder]

Okay, I'm getting a little farther. Here's the new outcome:

1. shut down
2. remove power
3. restore power and boot
4. stop ModemManager
5. run wrapper.py chip info
6. it yields the chip info output expected, but then it won't close the channel and I get

INFO: Close channel 01
close channel_id: 1
Error executing command: error: operation failed: Unknown status 0x87430003

after that, nothing works again without starting back with (1).

[stich86]

Okay, I'm getting a little farther. Here's the new outcome:

1. shut down

2. remove power

3. restore power and boot

4. stop ModemManager

5. run wrapper.py chip info

6. it yields the chip info output expected, but then it won't close the channel and I get

INFO: Close channel 01

close channel_id: 1

Error executing command: error: operation failed: Unknown status 0x87430003

after that, nothing works again without starting back with (1).

What's happen if you remove -p form mbimcli?

[AndySchroder]

https://aleksander.es/data/20210421%20-%20Introduction%20to%20ModemManager.pdf page 22 talks about what the mbim-proxy proxy does. Apparently it allows you to keep ModemManager running if you use it.