qmi_wwan add_mux/del_mux

[Aleksander Morgado]

Hey,

I've added Subash in CC of the thread.

On Thu, Jan 21, 2021 at 11:23 PM Daniele Palmas <dnlplm at gmail.com> wrote:
>
> Il giorno gio 21 gen 2021 alle ore 17:52 Aleksander Morgado
> <aleksander at aleksander.es> ha scritto:
> >
> > Hey again,
> >
> > > Say I create a new muxed interface for mux id 5:
> > >   echo 5 > /sys/class/net/wwan0/qmi/add_mux
> > > A new qmimux0 interface is created.
> > >
> > > Is there any way to know which mux id was used to create the qmimux0
> > > looking just at sysfs or some other way? In other words, how would I
> > > know what the mux id is for a given qmimuxN interface that may not
> > > have been created by me?
> > >
> > > Also, say that I have 2 different programs creating this kind of
> > > interfaces, and both use the qmi/add_mux attribute. If they both run
> > > at the same time (asking for different mux ids), and two interfaces
> > > qmimux0 and qmimux1 are created, how can each program know which was
> > > the interface corresponding to the mux id they requested?
> > >
> > > Not sure I'm missing something, but I didn't find a way to do this
> > > kind of matchings. If the virtual qmimux interface exposed a sysfs
> > > attribute specifying which is the mux id they correspond to, the
> > > matching would be much easier. Would that be possible?
> > >
> > > For context, I'm trying to work on adding support for this interface
> > > in libqmi, with the new qmi_device_add_link() interface that is right
> > > now only available when using rmnet with netlink.
> > >
> >
> > In the context of multiplexing QMUX data sessions, Stephan also
> > suggested we revive this old patch that never got a v2 in the LKML:
> > https://lore.kernel.org/netdev/1530066614-24995-1-git-send-email-subashab@codeaurora.org/
> >
> > Adding support to use rmnet on top of qmi_wwan seems like a good idea,
> > and we would be able to use the implementation we already have for
> > e.g. IPA, e.g.:
> > https://gitlab.freedesktop.org/mobile-broadband/libqmi/-/merge_requests/184#note_715900
> >
> > What do you all think?
>
> I think that would be the best solution, since it also allows
> homogeneity with PCIe MHI.
>
> Reading again the comments, it seems to me that the patch was not too
> far to be acceptable, so maybe it would be worth looking at it again.
>

Subash, any reason why the patch was forgotten and no v2 proposed? Is
there something we can do to push it forward?

-- 
Aleksander
https://aleksander.es