Fibocom L850-GL hangs upon connect.

[Daniel Wood]

Yes, it does have two AT ports.

However, once ttyACM0 gets tied up and times out after 10 command retries,
ModemManager removes the modem:
ModemManager[13213]: <error> [1533754896.224557] (tty/ttyACM0) at port
timed out 10 consecutive times, marking modem
'/org/freedesktop/ModemManager1/Modem/0' as invalid
ModemManager[13213]: <debug> [1533754896.224790] Removing from DBus bearer
at '/org/freedesktop/ModemManager1/Bearer/0'
ModemManager[13213]: <debug> [1533754896.224833] [device
/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5] unexported modem from
path '/org/freedesktop/ModemManager1/Modem/0'
ModemManager[13213]: <debug> [1533754896.224854] Periodic signal checks
disabled
ModemManager[13213]: <debug> [1533754896.225124] (ttyACM0) device open
count is 0 (close)
ModemManager[13213]: <debug> [1533754896.225150] (ttyACM0) closing serial
port...
ModemManager[13213]: <debug> [1533754896.279512] (ttyACM0) serial port
closed
ModemManager[13213]: <debug> [1533754896.279592] (ttyACM0) forced to close
port
ModemManager[13213]: <debug> [1533754896.279621] (ttyACM2) device open
count is 0 (close)
ModemManager[13213]: <debug> [1533754896.279637] (ttyACM2) closing serial
port...
ModemManager[13213]: <debug> [1533754896.279670] (ttyACM2) serial port
closed
ModemManager[13213]: <debug> [1533754896.279697] (ttyACM2) forced to close
port
ModemManager[13213]: <debug> [1533754896.279718] Modem (Generic)
'/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5' completely disposed

This whole time, I'm able to connect to ttyACM2 with minicom and issue AT
commands and get replies. ModemManager is only treating ACM0 as the modem
and doesnt care about ACM2 (even though it will identify it as an AT
command port)
I've attached a complete boot log showing the process with both
ModemManager and NetworkManager in debug mode:
https://gist.github.com/danielewood/8e19a0832266638c4da2f163ac3520a8

I also came across a command that may be of interest, the standard AT
command of AT+CLAC prints all supported AT commands for this modem. That
may be useful in identifying modems in the future. I included the output of
that command in the linked gist as well.


If this modem is going to end up stuck with pure PPP and therefore maxing
out at 25Mbps, then I'm not too concerned anyways since its use is rather
limited. I just wish I could figure out how to switch this thing to MBIM
(Tried everything listed in the AT Command reference guide, including
factory resets and defaults.).

Thanks,
-Dan


On Wed, Aug 8, 2018 at 4:41 AM, Aleksander Morgado <aleksander at aleksander.es
> wrote:

> Hey!
>
> On Wed, Aug 8, 2018 at 6:34 AM, Daniel Wood <daniel at woods.us> wrote:
> > I have been given a Fibocom L850-GL that seems to be stuck in NCM mode.
> > As I have not had any luck changing the mode back to MBIM:
> > ModemManager[25270]: <debug> [1533696762.104669] (ttyACM0): -->
> > 'AT+GTUSBMODE?<CR>'
> > ModemManager[25270]: <debug> [1533696762.121517] (ttyACM0): <--
> > '<CR><LF>+CME ERROR: 4<CR><LF>'
> > ModemManager[25270]: <debug> [1533696831.512880] (ttyACM0): -->
> > 'AT+GTUSBMODE=2<CR>'
> > ModemManager[25270]: <debug> [1533696831.530829] (ttyACM0): <--
> > '<CR><LF>+CME ERROR: 4<CR><LF>'
> >
> > I figured I would try to see how it works under the latest version of
> > ModemManager, but as soon as you try to actually connect to the internet,
> > the serial port locks up. Now, given the state of this modem, it may have
> > nothing to do with ModemManager. Since it may possibly or this may
> assist in
> > adding support for these Intel XMM based chipsets, I have collected all
> the
> > information I could think of to make it available to you guys, including
> > debug logs and bus trees.
> >
> > [85855.509892] usb 2-1.5: New USB device found, idVendor=8087,
> > idProduct=07f5
> > [85855.509896] usb 2-1.5: New USB device strings: Mfr=0, Product=0,
> > SerialNumber=0
> > [85856.714197] usb 2-1.5: USB disconnect, device number 43
> > [85861.288570] usb 2-1.5: new high-speed USB device number 44 using
> ehci-pci
> > [85861.405658] usb 2-1.5: New USB device found, idVendor=8087,
> > idProduct=095a
> > [85861.405662] usb 2-1.5: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=3
> > [85861.405665] usb 2-1.5: Product: MODEM + 2 CDC-ACM + 3 CDC-NCM + SS
> > [85861.405667] usb 2-1.5: Manufacturer: Intel Corp.
> > [85861.405669] usb 2-1.5: SerialNumber: 004999010640000
> >
> >
> > It is 3000+ lines of info, so I created a Gist:
> > https://gist.github.com/danielewood/1022919b7547c50fb514a652aa3ec1f3
> >
> > Let me know if there is any other information that is needed and I'll
> pull
> > it. Also, I can create a temporary linux install on a junk USB drive and
> > provide you with remote ssh access to the machine if someone wants to
> have
> > full access and do whatever they want. The broadband plan is unlimited,
> so
> > I'm not at all worried bandwidth use.
> >
> > I also decided to compile ModemManager from the git master branch, those
> > results are at the end of the page.
> >
>
> I'm currently working on improving the L850-GL support within
> ModemManager, but I was only focusing in the MBIM setup, not in the
> NCM one. Parts of the plugin provide AT-based features even for the
> MBIM mode (e.g. mode/band switching with AT+XACT) so those could be
> reused.
>
> We don't have NCM support for Intel XMM based devices yet... we have a
> staging "infineon" plugin with some support to start the data
> connection over the NCM, but we never got to test it properly so it's
> not in git master yet. I assume that as soon as you connect the modem
> it runs in PPP mode, and that is why you lose the AT port, but this
> device should have 2 AT ports, doesn't it?
>
> --
> Aleksander
> https://aleksander.es
>
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