Network Manager uses wrong 3G modem

[David Monniaux]

Binary package hint: modemmanager

I have both an internal 3G modem (on /dev/ttyACM0, ACM1 and ACM2), which I don't intend to use, and an external dongle (on /dev/ttyUSB0 and USB1). The external dongle shows correctly in the Network Manager dialog as "Mobile Broadband".

Modem-manager logging shows (Extract):
** (modem-manager:3014): DEBUG: Added modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6
** (modem-manager:3014): DEBUG: Exported modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6 as /org/freedesktop/ModemManager/Modems/0
** Message: (Ericsson MBM): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6 claimed port ttyACM0
** Message: (Ericsson MBM): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6 claimed port ttyACM1
** Message: (Ericsson MBM): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6 claimed port ttyACM2
** Message: (Huawei): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-4 claimed port ttyUSB0
** (modem-manager:3014): DEBUG: Added modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-4
** (modem-manager:3014): DEBUG: Exported modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-4 as /org/freedesktop/ModemManager/Modems/1
** Message: (Huawei): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-4 claimed port ttyUSB1

I don't wish to use the Ericsson (/org/freedesktop/ModemManager/Modems/0) but instead the Huawei (/org/freedesktop/ModemManager/Modems/1).

However, when I try to connect, modem-manager tries to use /dev/ttyACM0 as shown by debug mode:

** Message: Modem /org/freedesktop/ModemManager/Modems/0: state changed (disabled -> enabling)
** (modem-manager:3014): DEBUG: (ttyACM0): --> 'AT&F E0 V1 X4 &C1 +CMEE=1<CR>'
** (modem-manager:3014): DEBUG: (ttyACM0): <-- '<CR><LF>OK<CR><LF>'
** (modem-manager:3014): DEBUG: (ttyACM0): --> 'AT*ENAP=0<CR>'
** (modem-manager:3014): DEBUG: (ttyACM0): <-- '<CR><LF>ERROR<CR><LF>'
** (modem-manager:3014): DEBUG: Got failure code 100: Unknown error
** (modem-manager:3014): DEBUG: (ttyACM0): --> 'AT+CFUN=1<CR>'
** (modem-manager:3014): DEBUG: (ttyACM0): <-- '<CR><LF>+CME ERROR: 272<CR><LF>'

** (modem-manager:3014): WARNING **: Invalid error code
** (modem-manager:3014): DEBUG: Got failure code 100: Unknown error
** Message: Modem /org/freedesktop/ModemManager/Modems/0: state changed (enabling -> disabled)

That's not really surprising, since the internal modem is turned off using the RFKILL physical switch.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: modemmanager 0.3-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.32-25.44-generic 2.6.32.21+drm33.7
Uname: Linux 2.6.32-25-generic i686
NonfreeKernelModules: wl
Architecture: i386
Date: Wed Oct 6 16:20:58 2010
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: modemmanager

[David Monniaux (david-monniaux)]

An obvious workaround is to disable the internal modem in the BIOS, but of course that does not solve the bug. :-)

[David Monniaux (david-monniaux)]

I have found the source of the problem. When I established the broadband profile, the Dongle had not yet been fully recognized by the kernel (it is a bit slow - need to start USB-storage and MMC devices, then activate the tty ports). As a consequence, it was created using device 0 (internal GSM). Thus, regardless of what network manager saw as currently active devices, it always tried to use device 0.

One problem is that the interface for defining profiles does not show to which device the profile is associated, nor does it allow changing it.

So rather than a true-blooded bug it's a conjunction of slow detection of devices and some user interface lacking relevant information and controls.

[Mathieu Trudel-Lapierre (cyphermox)]

Yup, some USB devices are rather slow to be detected. I can confirm this with my own ZTE MF636.

[Aleksander Morgado (aleksander-m)]

When more than one broadband devices are found, nm-applet shows not only "Mobile broadband" but also the Vendor/Model of each device (IIRC). We should probably fix it so that the Vendor/Model is also shown when a single device is found.

I happen to have exactly the same issue in my laptop, with the internal Gobi modem and the external dongles. Sometimes the Gobi modem is not detected, and sometimes it is. So when I plug in my external dongle, there's some time when I do not know whether the Mobile broadband shown in nm-applet refers to the internal one or the external one.

[Mathieu Trudel-Lapierre (cyphermox)]

Well, we don't really want to show all that much information becasue in most cases there is only one device, and the vendor/model string can be quite long.

I'm not sure if it's that much of an issue; the actual device to be used it shown in the the first page of the new connection wizard.

Should this just be marked as Invalid or is there more that needs to be done?