[review] Fix subscribed event list management in the mbim-proxy

[Aleksander Morgado]

> > >> > I've observed some out-of-sync issue between ModemManager and libmbim
> > >> > after applying this patchset .
> > >> >
> > >> > "mbimcli -p -d /dev/cdc-wdm0 --query-registration-state" reports the
> > >> > modem has registered to the home network, while "mmcli -m 0" reports
> > >> > modem state is "enabled" but not "registered".  I also observed once
> > >> > that the power/radio state was also out-of-sync between libmbim and
> > >> > ModemManager.
> > >> >
> > >> > Have you noticed any behavior difference?
> > >> >
> > >>
> > >> Hum... no, I haven't observed any difference, which doesn't mean there
> > >> isn't any. A wild guess here, maybe we're actually de-registering from
> > >> the standard service indications with the new patches? I thought that
> > >> was not possible, at least not with the few devices I tested with. In
> > >> the worst case scenario, we can just bring back the logic that
> > >> explicitly registers to all indications in the basic services, but we
> > >> should make sure that's the problem first.
> > >>
> > >> Which device are you using for testing?
> > >> Could you get debug logs *in the mbim-proxy* while testing this?
> > >> (you're using the proxy, right?)
> > >
> > >
> > > Yep, I was using the proxy. I didn't pay attention to the exact steps to reproduce the issue as I just observed it by chance. IIRC, the modem (Fibocom L850) was initially registered to network at boot. Then I used mmcli to disable it, and then to reenable it. I noticed the mmcli reported the modem wasn't registered. Then l used mbimcli to query but it said registered to home. I wasn't too sure which one lied. Also IIRC, the modem used to automatically register to home network after been enabled by MM.
> > >
> >
> > I think I found the issue. I believe it's a mix between incorrectly
> > trying to enable QMI-over-MBIM indications in the Intel-based MBIM
> > modems and also assuming incorrectly that we cannot disable the
> > indications of standard services.
> >
> > These two MRs should fix the issue you've seen, please test them and
> > report what you see.
> > https://gitlab.freedesktop.org/mobile-broadband/libqmi/merge_requests/8
> > https://gitlab.freedesktop.org/mobile-broadband/libmbim/merge_requests/4
> >
> > With these two things in place, I can successfully get
> > "indicate-status" messages for the basic services on my L850.
> >
> > There is one additional thing that we could fix, which is the fact
> > that when we enable the QMI-over-MBIM indications via MBIM device
> > service subscribe list, we're effectively disabling all standard
> > service indications that were automatically enabled for us, but that
> > is not an issue for ModemManager where we only enable those CIDs for
> > which we expect to receive indications. Not a big deal I think.
> >
>
> That seems to address the issue I observed on Fibocom L850. I don't
> have a QMI-MBIM device to test with at the moment.
>

Thanks for checking. I've tested them myself with several
Qualcomm-based devices supporting QMI-over-MBIM, where the same kind
of bug was observed.

Dan, would you like to review the MRs?

-- 
Aleksander
https://aleksander.es