nm-pppd-plugin does not start

[matti kaasinen <matti kaasinen gmail com>]

Hi,

For the firstly, sorry about long story..

Background:
=========

I'm trying to integrate Huawei 3131 modem, VID=21d1. Original PID=14fe that switches to PID=1506.

I'm working on am335x based embedded board running yocto/linux-ti-staging based Linux with 4.1 kernel. NM version is 0.9.8.10 and MM version 1.4.2. Board is using systemd.

Base problem is that most likely modem firmware is broken so that it claims supporting ndisdup, but in fact it does not. This revealed when I first tried using connman/ofono. Connection went up to stage where connection was opened wtih  AT^NDISDUP=1,1. Following  AT^DHCP? returned only OK without any connection details.

However my desktop machine - Ubuntu 14.04 opens connection quite smoothly. It has NM version 0.9.8.8 and MM version 1.0.0. Somehow it does not care about this ndisdup problem, but instead opens connection using ppp - no problem at all.

Main difference found from sysfs is that Ubuntu opens only /dev/ttyUSB0  /dev/ttyUSB2  /dev/ttyUSB3 devices for this modem whereas am335x board opens
/dev/ttyUSB0  /dev/ttyUSB1  /dev/ttyUSB2 /dev/cdc-wdm0 and /net/wwan0

if I execute following command after plugging in modem:

nmcli d

Ubuntu provides:

ttyUSB3    gsm               disconnected

am335x board do not provide  have this line

If I execute following command on am335x board:
mmcli -m 0 --simple-connect="apn=internet"

Everything seems going well, solid blue led swithes on, but there is no interface brought up.

If I start modem connection from nm app on Ubuntu, ppp connection starts and it is brought to interfaces. From logs it seems that it also is using simple-connect method.

If I use udev rules to ignore cdc-wdm0 and net/wwan0 on am335x board, simple-connect proceeds up tp "all done", but no ppp is started an in fact now even the led is not having solid blue. However, if I start pppd manually at this point, connection is established quite well.
I have tried to reproduce Ubuntu settings.
1) /etc/NetworkManager/NetworkManager.conf with following contents:
[main]
plugins=keyfile
dns=dnsmasq

2) /etc/NetworkManager/system-connections/Operator with following contents:
[connection]
id=Operator
uuid=b9cbaa78-8856-4c82-915b-702048ab3b85
type=gsm
permissions=user:root:;
autoconnect=true
timestamp=0

[gsm]
number=*99#
apn=internet

[ipv4]
method=auto

[serial]
baud=115200

Differences bitween Ubuntu and am335x board:
1) Note that Ubuntu uses upstart and am335x board systemd.
2) Ubuntu lists one line for each of files in /etc/NetworkManager/system-connections folder whereas am335x seems ignoring these settings.

net/ppp0
-----------
Ubuntu:
ModemManager[22598]: <debug> [1456479663.774029] [mm-manager.c:270] device_added(): (net/ppp0): could not get port's parent device

am335x: no reference for net/ppp0

NM in Ubuntu starts reports reporting ppp with following lines:
NetworkManager[22606]: <info> pppd started with pid 23181
Plugin /usr/lib/x86_64-linux-gnu/pppd/2.4.5/nm-pppd-plugin.so loaded.
** Message: nm-ppp-plugin: (plugin_init): initializing
** Message: nm-ppp-plugin: (nm_phasechange): status 3 / phase 'serial connection'
Using interface ppp0
Connect: ppp0 <--> /dev/ttyUSB0

all PPP messages from am335x

plugins/huawei/mm-plugin-huawei.c:543] grab_port(): (tty/ttyUSB0) Port flagged as PPP

src/mm-port-serial-at.c:440] debug_log(): (ttyUSB2): <-- '<CR><LF>+CGDCONT: (1-11),"IP",,,(0-2),(0-3)<CR><LF>+CGDCONT: (1-11),"IPV6",,,(0-2), (0-3)<CR><LF>+CGDCONT: (1-11),"IPV4V6",,,(0-2),(0-3)<CR><LF>+CGDCONT: (1-11),"PPP",,,(0-2),(0-3)<CR><LF><CR><LF>OK<CR><LF>'

src/mm-modem-helpers.c:783] mm_3gpp_parse_cgdcont_test_response(): Unhandled PDP type in CGDCONT=? reply: 'PPP'

QUESTIONS:

=========

1) What is missing in my set-up?

2) net/ppp0. What is required to get am335x MM creating ppp0 interface like Ubuntu does?

3) It is told in the MM package that there is no need starting on boot - dbus will start on demand. What event does this as MM does not start at all if service is not enabled by default

thanks,

Matti