Fibocom L850-GL hangs upon connect.

[Aleksander Morgado]

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