Re: Sierra Wireless EM9191 integration issues in mhi+wwan

[Aleksander Morgado <aleksander@aleksander.es>]

Hey!

> > > On our setup, using i.MX6DL based board and a PCIe Sierra Wireless
> > > EM9190 module, running Yocto and Linux 5.13, we don't have much
> > > success
> > > for the moment, qmi and mbim commands very often end in timeout.
> > >
> > > Otherwise, when responses are received, we also can observe strange
> > > things: unexpected messages, response to previous commands or queue
> > > buffer issue.
> > >
> >
> > Once all my boot reliability issues seem solved, I've also started to
> > notice what you mean here. If I run a normal ModemManager build with
> > both QMI and MBIM enabled, MM will try to probe both the QMI and MBIM
> > ports. When that happens, I have no idea why, the modem gets in some
> > weird state with commands timing out and what not. Maybe it's because
> > we're using both ports at the same time, maybe it's because we run
> > QMI
> > on both the QMI and MBIM ports, no idea, the only thing I know is
> > that
> > if you choose to use either one or the other, the whole setup is
> > fully
> > stable.
> >
> > E.g. I'm right now testing my build after compiling ModemManager
> > using
> > --without-mbim (so QMI only), and I have absolutely no error.
>
> That's very good news!
>
> > Another
> > option if you don't want to rebuild MM is to flag the MBIM or the QMI
> > port as ID_MM_PORT_IGNORE with udev rules, which is very likely what
> > I'll end up doing in upstream ModemManager to have a proper default.
> >
> > I was thinking in preparing and sending for review the EM91xx entry
> > for drivers/bus/mhi/pci_generic.c, but it's mostly based on what you
> > suggested in the Sierra Wireless forum, so not sure if you'd like to
> > send it yourself here?
>
> I can send it myself here, and I add you as developer if you'd like ?
>

Then please send it yourself, I just suggested a couple minor changes
on the work you did :)
Thanks!

-- 
Aleksander
https://aleksander.es