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

[Dan Williams]

On Tue, 2018-11-06 at 12:46 +0100, Aleksander Morgado wrote:
> > > > > > 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_requ
> > > ests/8
> > > https://gitlab.freedesktop.org/mobile-broadband/libmbim/merge_req
> > > uests/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?

Merged.

Dan