TOBY-L210 does not detected by ModemManager deamon at boot time

[Aleksander Morgado]

Hey,

> > -----Original Message-----
> > From: Aleksander Morgado <aleksander at aleksander.es>
> > Sent: Monday, October 29, 2018 9:48 AM
> > To: Baryshnikov, Maxim (Digiteq Automotive)
> > <Maxim.Baryshnikov at digiteqautomotive.com>; modemmanager-
> > devel at lists.freedesktop.org
> > Subject: Re: TOBY-L210 does not detected by ModemManager deamon at boot
> > time
> >
> > On 10/23/18 8:19 PM, Baryshnikov, Maxim (Digiteq Automotive) wrote:
> > > Hello all,
> > >             I'm struggling with the following issue. On my system, the
> > ModemManager (1.8.2) cannot detect TOBY-L2 modem at boot time. I have
> > allowed all "filter rules", but the situation is the same as for the default rules set.
> > However, if I manually reset the modem with detaching it from the system (send
> > AT+CFUN=16 to it), the ModemManager successfully detects it.
> > >             ModemManager is compiled with --without-mbim and -without-qmi, but
> > there should be no influence on detection, I guess..
> > >             Do you have any ideas what to check to solve this? Is there something
> > wrong with udev? Thank you in advance for any piece of information..
> > > Kind regards,
> >
> > How are you sending AT+CFUN=16 to the modem while ModemManager is
> > running? Please understand that no other program can be using the TTY port if you
> > expect ModemManager to use it. Maybe you have a minicom session open while
> > MM should be probing the port at the same time?
>
> I don't think that this is happenning at the boot time. I've found a workaround - to retrigger udev event on my device right after the ModemManager service starts.
>
> ExecStart=@sbindir@/ModemManager
> ExecStartPost=/bin/udevadm trigger /sys/devices/soc0/amba/e0002000.usb/ci_hdrc.0/usb1/1-1/1-1.2
>
>
> > Without looking at the ModemManager debug log it's hard to say what's really
> > happening. Could you get it?
> > https://www.freedesktop.org/wiki/Software/ModemManager/Debugging/
>
> I've found nothing much interesting there, it just does not probe ttyACM ports without having an udev event detected first..
>
> Oct 29 09:30:54 zynq7 ModemManager[179]: <debug> [1540805454.220980] (tty/ttyACM0): adding device at sysfs path: /sys/devices/soc0/amba/e0002000.usb/ci_hdrc.0/usb1/1-1/1-1.2/1-1.2:1.2/tty/ttyACM0
> Oct 29 09:30:54 zynq7 ModemManager[179]: <debug> [1540805454.221302] (tty/ttyACM0): port not candidate
> Oct 29 09:30:54 zynq7 ModemManager[179]: <debug> [1540805454.221565] (tty/ttyACM1): adding device at sysfs path: /sys/devices/soc0/amba/e0002000.usb/ci_hdrc.0/usb1/1-1/1-1.2/1-1.2:1.2/tty/ttyACM1
> Oct 29 09:30:54 zynq7 ModemManager[179]: <debug> [1540805454.221874] (tty/ttyACM1): port not candidate
> Oct 29 09:30:54 zynq7 ModemManager[179]: <debug> [1540805454.222126] (tty/ttyACM2): adding device at sysfs path: /sys/devices/soc0/amba/e0002000.usb/ci_hdrc.0/usb1/1-1/1-1.2/1-1.2:1.2/tty/ttyACM2
> Oct 29 09:30:54 zynq7 ModemManager[179]: <debug> [1540805454.222410] (tty/ttyACM2): port not candidate
>
> That is probably a problem in udev on my system. It behaves wierd..
>

That totally looks like some udev related issue indeed. The "port not
candidate" logs will happen if the ttyACM ports aren't flagged with
ID_MM_CANDIDATE, which is one of the tags added by the ModemManager
udev rules in /lib/udev/rules.d/. When the system boots and udev
detects the devices, the rules should be executed and the tag added,
and for some reason that is not happening in this setup.

-- 
Aleksander
https://aleksander.es