Re: Support for HP lt4112 Gobi 4G Modem

[Dan Williams <dcbw redhat com>]

On Fri, 2014-11-14 at 22:43 +0100, Martin Hauke wrote:
> Hi,
>
> On 14.11.2014 21:12, Dan Williams wrote:
>
> > I see that QMI works on the device, and that would be the preferred
> > method to manage it.  If you keep the qmi_wwan changes, the ModemManager
> > should be able to handle the device as a QMI device and use the cdc-wdm0
> > interface for control (QMI commands) and the network interface for data.
> >
> > MBIM might work too, but I"m not sure what the driver binding situation
> > would be there yet.  Since QMI seems to work lets try that first.
>
> I've just tested an LTE-connection via qmi/wwan with ModemManager 1.0.0
> without any problems.
> However the maximum downlinkspeed wasn't better than before with the
> AT-interface and was nearly the same as on Windows 8.1 (which seems to
> use MBIM).
>
> Are there any known issues with ModemManager when exposing the AT- and
> the QMI-interfaces in parallel ?

There aren't any known issues, but you usually cannot use them in
parallel for data sessions.  eg, you cannot typically have a ppp session
going on the AT port *and* a QMI data session on the 'net' port at the
same.  Firmware really doesn't like this, in my experience.

Note that ModemManager *may* use the AT port for some operations if the
device's QMI (or MBIM) firmware doesn't expose certain functionality.
But some devices expose multiple AT ports (like yours does) and
ModemManager will only use one.

> > > Interestingly the device also expose a CCID compatible smartcard interface.
> > > Unfortunately my naive approach to add support to the pcsc-lite ccid
> > > driver adding USB vendor/product-id/description to
> > > ifd-ccid.bundle/Contents/Info.plist did not work (see attachment).
> > >
> > > Has anyone worked with those types of PCSC-interfaces before?
>
> Any thoughts on this?
> It would be really cool to have this working since you can then send raw
> APDUs to the SIM.

ModemManager doesn't claim the PCSC port, so I guess any external
application that could speak the right protocol over that port could use
it for PCSC stuff.  I haven't looked into it though.

Dan