Ubuntu
modemmanager package

Sierra MC8775 wrong ttyUSB for data chosen?

Bug #504035 reported by Norbert Goebel
16
This bug affects 3 people
Affects Status Importance Assigned to Milestone
ModemManager
Expired
Medium
modemmanager (Ubuntu)
Incomplete
Undecided
Unassigned

Bug Description

Hi,

I am not sure if my guess, that mm chooses the wrong tty for data and by this leaving the data port "open" as at command port is true, but I am sure something is not working right atm and this is my best bet ;)

I am using a Thinkpad T61 with build in mini-pcie sierra wireless wwan MC8775 with USB ID 1199:6813.
MM version is 0.2.git.20091014t233208.16f3e00-0ubuntu1 on karmic amd64.
Checking the logs mm uses ttyUSB0 as the data port to open connections which leaves ttyUSB2 as the designated AT Command port, but when I try to use this with minicom I
a) can't see my input in the terminal
b) can't get any response on at commands except OK or ERROR
regardless if I try this while connected or unconnected.

If the modem is unconnected I can minicom to ttyUSB0 and use any supported AT Command (like AT!GSTATUS?) with normal behaviour - long answers, typing visible...
ttyUSB2 still behaves the same strange way if the modem is unconnected.

This leads me to my guess (as sierra for some modems uses ttyUSB0 as data, for others ttyUSB2 and the free other for commands), that mm probably should use ttyUSB0 for commands and ttyUSB2 for data.

As I need to get some info from the card to monitor signalstrenght and some more parameters I need a working command port.

Is there any easy way to patch mm to use the second detected modem port (ttyUSB2) for the data connection (while probably still using ttyUSB0 for commands) ?

Regards,
Norbert

Revision history for this message
Peter Meiser (meiser79) wrote :

I can confirm this issue. The upstream bug report is at https://bugzilla.gnome.org/show_bug.cgi?id=598939

Changed in modemmanager:
status: New → Confirmed
Revision history for this message
Norbert Goebel (nospam-edpfau) wrote : Re: [Bug 504035] Re: Sierra MC8775 wrong ttyUSB for data chosen?

Hi,

many thanks for this link and for the valuable info it contains.
I didn't even know about the ati command and will check as soon as I am
back on linux ;)
I knew that there must be a way to talk to modemmanager via dbus and the
linked page confirms this.

But as always it does give specific info on how often modemmanager asks
the modem for new info and how much latency this my app to d-bus to
modem and back communication introduces.

Sounds like you are trying to monitor stuff yourselve, too. Have you
ever tried using wvdial and not using networkmanager/modemmanager with
the sierra? I think I will try this way instead of waiting for a bugfix
on modemmanager.

Funny thing is, that logging status information on the sierra card this
is easier done on windows than on linux.
And it would be a much more portable solution to not indroduce d-bus on
linux side and use serial on windows but use serial on linux and windows
especially as it should be possible on both if modemmanager would not
interfere.

Regards,
Norbert

Whoopie schrieb:
> I can confirm this issue. The upstream bug report is at
> https://bugzilla.gnome.org/show_bug.cgi?id=598939
>
> ** Bug watch added: GNOME Bug Tracker #598939
> https://bugzilla.gnome.org/show_bug.cgi?id=598939
>
> ** Changed in: modemmanager
> Status: New => Confirmed
>
>

Revision history for this message
Bruce Wolfe (wolfedu) wrote :

I have the same issue with my Sierra MC8780 card EXCEPT the devices are the other way around ... that is MM tries to use ttyUSB2 as the DATA and on this card ttyUSB0 is the DATA .

Unfortunately Sierra produce some cards with USB0 as DATA and others with USB2 as DATA ... it would appear that MM is choosing the wrong device in at least both of these card instances which would suggest the probing algorithm is incorrect or at least using the wrong criteria to make the decision.

Regards,
Bruce

Revision history for this message
Bipolar (bipolar) wrote :

I've previously reported a bug ( https://bugs.launchpad.net/ubuntu/+source/modemmanager/+bug/557449 ) which is very similar with a sierra wireless 885. The data port is ttyUSB4, but mm is trying to use ttyUSB3.

Revision history for this message
Marius B. Kotsbak (mariusko) wrote :

Norbert, are you using Ubuntu? If so, could you please indicate if you still see the problem, and then run in a terminal "apport-collect 504035".

Changed in modemmanager:
importance: Undecided → Unknown
status: Confirmed → Unknown
Changed in modemmanager (Ubuntu):
status: New → Incomplete
Revision history for this message
Marius B. Kotsbak (mariusko) wrote :

Also, could you please get debug logs:

https://wiki.ubuntu.com/DebuggingModemmanager

and attach those to the upstream bug report: https://wiki.ubuntu.com/DebuggingModemmanager

Revision history for this message
Norbert Goebel (goebel) wrote :

Marius,

I still use Ubuntu but karmic is long gone. So is the laptop with the sierra card, which I sold months ago.
As far as I remember modemmanager never worked correctly me with the sierra card as it used the wrong ttyUSB device for the data connection and thus blocking my access to needer AT commands.

My workaround has alway been to deinstall modemmanager and use wvdial.

Revision history for this message
Marius B. Kotsbak (mariusko) wrote :

Okay, unfortunate that you are unable to test if this is fixed now. The upstream bug report indicates that it is supposed to be fixed. We just leave this bug report as incomplete in case somebody else can confirm if this bug is fixed now.

Bug Watch Updater (bug-watch-updater)
Changed in modemmanager:
importance: Unknown → Medium
status: Unknown → Expired
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