Sierra Wireless AirPrime EM919X support

Tue Aug 10 09:23:07 UTC 2021

On Mon, 9 Aug 2021 at 23:26, Aleksander Morgado <aleksander at aleksander.es>
wrote:

> Hey Thomas!
>
> > I'm trying to use ModemManager with a Sierra Wireless AirPrime EM919X,
> > based on a Snapdragon X55 5G Modem, without success.
> >
> > The EM919X is connected to an i.MX6QDL through a MHI bus on top of a
> > PCIe gen2 bus.
> >
> > I'm using the kernel 5.13.6, modemmanager 1.32.4, libqmi 1.30.0 and
> > libmbim 1.26.0.
>
> Wow, that's a MM version from the future! It's 1.16.8 according to
> your logs though ;)
>
> >
> > Aug  9 15:32:54 target daemon.info dbus-daemon[435]: [system]
> > Activating service name='org.freedesktop.ModemManager1' requested by
> > ':1.1' (uid=0 pid=507 comm="/usr/sbin/NetworkManager ") (using
> > servicehelper)
> > Aug  9 15:32:54 target daemon.info ModemManager[531]: <info>
> > ModemManager (version 1.16.8) starting in system bus...
> > Aug  9 15:32:55 target daemon.info dbus-daemon[435]: [system]
> > Successfully activated service 'org.freedesktop.ModemManager1'
> > Aug  9 15:32:55 target daemon.info NetworkManager[507]: <info>
> > [1628523175.0109] modem-manager: ModemManager not available
> > Aug  9 15:32:55 target daemon.info NetworkManager[507]: <info>
> > [1628523175.1141] modem-manager: ModemManager now available
> > Aug  9 15:32:56 target daemon.warn ModemManager[531]: <warn>
> > [wwan0p1QCDM/qcdm] failed to open serial device
> > Aug  9 15:32:56 target daemon.warn ModemManager[531]: <warn>  [plugin-
> > manager] task 0,wwan0p1QCDM: error when checking support with plugin
> > 'generic': (wwan/wwan0p1QCDM) Failed to open QCDM port: Failed to open
> > QCDM port: -2
>
> Humm, that should not happen, right @Loic Poulain ? It's true that
> it's not a serial device, and I recall some patch avoiding to run
> config_fd() on non-serial devices, so it may be related.
>

Yes, but AFAIR, the patch was for AT (non-serial) ports, we should apply
the same kind of change here. I get the same issue on my side, but since
qcdm is not really used,  MM just ignore it without further issue.

> > Aug  9 15:32:56 target daemon.debug ModemManager[531]:
> > [/dev/wwan0p3QMI] Opening device with flags 'version-info, proxy'...
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]:
> > [/dev/wwan0p3QMI] created endpoint
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]: cannot connect
> > to proxy: Could not connect: Connection refused
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]: spawning new
> > qmi-proxy (try 1)...
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]: opening
> > device...
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]: cannot connect
> > to proxy: Could not connect: Connection refused
>
> There is something very wrong in this setup I think; MM tries to spawn
> a new qmi-proxy as there is none, but that fails. It shouldn't fail! I
> would assume the proxy could be failing to open the wwan0p3QMI port in
> the same way as the QCDM one, but wouldn't know.
>
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]: spawning new
> > mbim-proxy (try 1)...
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]:
> > [/dev/wwan0p2MBIM] Couldn't find descriptors file, possibly not using
> > cdc_mbim
> > Aug  9 15:32:56 target daemon.debug ModemManager[531]:
> > [/dev/wwan0p2MBIM] Fallback to default max control message size: 4096
>
> Wait, and this modem exposes both QMI and MBIM ports? I think this is
> new, first time I've seen this I think. If I'm not mistaken this is a
> decision that the manufacturer takes, right? I think the generic
> plugin will try to create a QMI based modem if it finds any QMI
> capable port, and otherwise fallback to create a MBIM based modem if
> it finds any MBIM capable port. Anyway, we didn't reach that point
> yet, just a heads up.
>

'Generic' X55 devices expose both MBIM and  QMI control ports, I'm going to
submit a change in the kernel to avoid that if it causes trouble. But last
time I tried with such a device, MM was just picking the QMI one for
control (generic plugin), as you said.

> > Aug  9 15:32:56 target daemon.debug ModemManager[531]:
> > [/dev/wwan0p3QMI] Checking version info (45 retries)...
> > Aug  9 15:32:57 target daemon.info ModemManager[531]: <info>  [base-
> > manager] couldn't check support for device
> > '/sys/devices/platform/soc/2100000.bus/2184200.usb/ci_hdrc.1/usb1/1-
> > 1/1-1.1': not supported by any plugin
> > Aug  9 15:32:57 target daemon.info ModemManager[531]: <info>  [base-
> > manager] couldn't check support for device
> > '/sys/devices/platform/soc/2100000.bus/2188000.ethernet': not supported
> > by any plugin
> > Aug  9 15:32:57 target daemon.debug ModemManager[531]: transaction 0x2
> > aborted, but message is not abortable
> > <...>
> > Aug  9 15:33:25 target daemon.debug ModemManager[531]: transaction 0x1e
> > aborted, but message is not abortable
> > Aug  9 15:33:26 target daemon.debug ModemManager[531]: proxy
> > configuration failed: closed
> > Aug  9 15:33:26 target daemon.debug ModemManager[531]:
> > [/dev/wwan0p2MBIM] channel destroyed
> > Aug  9 15:33:26 target daemon.debug ModemManager[531]: transaction 0x1f
> > aborted, but message is not abortable
> > <...>
> > Aug  9 15:33:41 target daemon.debug ModemManager[531]: transaction 0x2e
> > aborted, but message is not abortable
> > Aug  9 15:33:41 target daemon.info ModemManager[531]: <info>  [device
> > /sys/devices/platform/soc/1ffc000.pcie/pci0000:00/0000:00:00.0/0000:01:
> > 00.0] creating modem with plugin 'generic' and '3' ports
> > Aug  9 15:33:41 target daemon.warn ModemManager[531]: <warn>
> > [plugin/generic] could not grab port wwan0p3QMI: Cannot add port
> > 'wwan/wwan0p3QMI', unhandled port type
> > Aug  9 15:33:41 target daemon.warn ModemManager[531]: <warn>
> > [plugin/generic] could not grab port wwan0p2MBIM: Cannot add port
> > 'wwan/wwan0p2MBIM', unhandled port type
>
> Neither the QMI nor the MBIM probing were successful.
>

Maybe udev rules are not installed?

Regards,
Loic
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