MC7455 location support

Dan Williams dcbw at redhat.com
Thu Apr 13 18:30:32 UTC 2017


On Thu, 2017-04-13 at 17:21 +0000, Karoly Pados wrote:
> Hello,
> 
> > Ah, my mistake then. But I would have expected to see more location
> > methods supported if the modem was in QMI mode. Can you run:
> > 
> > qmicli --device-open-qmi -d /dev/cdc-wdm0 --get-service-version-
> > info
> 
> Attached. I needed to upgrade libqmi because my original version
> didn't have --device-open-qmi. I also recompiled MM after that before
> obtaining the attached files.
> 
> > also, if you have ModemManager debug logs, that would be great to
> > see
> > too so we can make sure things are being set up correctly.
> 
> Attached. Also output of mmcli -m 0 in separate file.

Thanks.  This shows your device is in fact in QMI mode, and that the
firmware doesn't implement the "PDS" (Position Determination Service)
that is normally used for this.

But it does appear to support the LOC service (location) which is a
newer service that ModemManager (and libqmi) doesn't yet support.  So I
think that's the current problem.

Dan

> > One other possibility: the modem is in MBIM mode, but ModemManager
> > has
> > some logic to use the MBIM QMI passthrough to set the Sierra "FCC
> > Auth"
> > command. MM doesn't yet have logic to try GPS through QMI while the
> > modem is in MBIM though.
> 
> How can I tell if this is what is happening? Can you tell from the
> debug log? It doesn't seem to mention "MBIM" at all. Or maybe I need
> to check this using another way?
> 
> All files I attached will tell you in the top how that output was
> created. I hope these will help narrow down what is missing. Let me
> know if there is anything else I can do.
> 
> Károly
> 
> 
> April 13, 2017 6:01 PM, "Dan Williams" <dcbw at redhat.com> wrote:
> 
> > On Thu, 2017-04-13 at 09:41 +0000, Karoly Pados wrote:
> > 
> > > Hello,
> > > 
> > > Thanks for your reply. Are you sure the modem is not already in
> > > QMI
> > > mode? MM is clearly using QMI to communicate with it (and I can
> > > also
> > > use qmicli -p), and also below URL states that this modem is a
> > > QMI
> > > raw-ip only modem.
> > 
> > Ah, my mistake then. But I would have expected to see more location
> > methods supported if the modem was in QMI mode. Can you run:
> > 
> > qmicli --device-open-qmi -d /dev/cdc-wdm0 --get-service-version-
> > info
> > 
> > also, if you have ModemManager debug logs, that would be great to
> > see
> > too so we can make sure things are being set up correctly.
> > 
> > One other possibility: the modem is in MBIM mode, but ModemManager
> > has
> > some logic to use the MBIM QMI passthrough to set the Sierra "FCC
> > Auth"
> > command. MM doesn't yet have logic to try GPS through QMI while the
> > modem is in MBIM though.
> > 
> > Dan
> > 
> > > https://sigquit.wordpress.com/2017/01/07/modemmanager-in-openwrt-
> > > take-2
> > > 
> > > Though I also admit I am not 100% sure, because the protocol
> > > relations and communication possibilities with the modem are not
> > > yet
> > > clear to me (I am quite new to this topic).
> > > 
> > > Though I am a developer myself, I don't have much experience with
> > > different modems yet. So while I can gladly try to implement
> > > support
> > > for my modem's GNSS AT command set, it might end up being very
> > > model-
> > > specific. With some pointers though about which source files and
> > > APIs
> > > to start with (I don't have a clue yet about MM's code either), I
> > > might give it a go if you don't mind.
> > > 
> > > Regards,
> > > 
> > > Károly
> > > 
> > > April 12, 2017 5:58 PM, "Dan Williams" <dcbw at redhat.com> wrote:
> > > 
> > > On Wed, 2017-04-12 at 13:21 +0000, Karoly Pados wrote:
> > > 
> > > > Hello,
> > > > 
> > > > I have a MC7455 form Sierra Wireless. It is working fine for
> > > > data
> > > > communication, but ModemManager doesn't seem to be able to
> > > > recognize
> > > > the locations services (GPS and A-GPS) provided by the modem. 
> > > > 
> > > > mmcli -m 0 --location-status
> > > > 
> > > > /org/freedesktop/ModemManager1/Modem/0
> > > > ----------------------------
> > > > Location |   capabilities: '3gpp-lac-ci'
> > > > > enabled: '3gpp-lac-ci'
> > > > > signals: 'no'
> > > > 
> > > > If I start ModemManager with the --debug flag and then issue
> > > > AT-
> > > > commands using --command by hand, I can get a GPS fix and
> > > > retrieve
> > > > the location using raw AT commands. (This also means that in my
> > > > case
> > > > there is no need to unlock location services using a password.)
> > > > 
> > > > I read on this list that the modem needs to be in QMI-mode for
> > > > MM
> > > > to
> > > > support location data. I think this is already the case because
> > > > when
> > > > I start MM in debug mode I can see it is using QMI to
> > > > communicate.
> > > > 
> > > > Is there anything else I can do or need to check to make
> > > > location
> > > > data in MM working? Or any way I can help to implement support
> > > > for
> > > > it?
> > > 
> > > At the moment, no. The device is likely in MBIM mode which is why
> > > you
> > > don't get location data. There are two options we are exploring
> > > for
> > > ModemManager:
> > > 
> > > 1) use the MBIM QMI passthrough to provide the location data that
> > > QMI
> > > can provide, which will work with this device because it's a
> > > Qualcomm-
> > > based one
> > > 
> > > 2) if that fails, see if we can use the AT ports for GPS
> > > 
> > > This is mainly just a problem for MBIM devices, because the MBIM
> > > protocol specification does not contain any GPS-related options.
> > > That
> > > is left to vendor proprietary methods, as you've discovered :)
> > > 
> > > So TLDR; you can't do this yet but it's at least being thought
> > > about/worked on. If you're interested in helping fix this, we can
> > > use
> > > either code or testing...
> > > 
> > > Thanks!
> > > Dan
> > > 
> > > > My software:
> > > > # uname -a
> > > > Linux a13-olinuxino 4.9.21 #2 SMP Mon Apr 10 10:29:48 CEST 2017
> > > > armv7l GNU/Linux
> > > > # ModemManager --version
> > > > ModemManager 1.6.2
> > > > ...
> > > > # qmicli --version
> > > > qmicli 1.16.0
> > > > ...
> > > > 
> > > > Thank you for your help, greetings,
> > > > 
> > > > Károly Pados
> > > > 
> > > > tec4data
> > > > finding of facts!
> > > > thoerl 35; 8621 thoerl; austria
> > > > mob +43 680 5577 310
> > > > uid atu44131505
> > > > mail kp at tec4data.at
> > > > http://www.tec4data.at
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