mobile broadband connection only works after replugging usb device

[Peter Schüller]

I have a GSM USB broadband modem which works nearly perfect in natty, with one exception:

If I just boot the computer and log into the system no network connection is there and I am not able to connect with the network manager applet.

If i plug out the modem, plug it again into USB, everything works.

I can even plugout the modem before logging in, plug it in again, and then login. The connection will be there. Without replugging it will not.

[Peter Schüller (schueller-p)]

I attached my dmesg as it could be helpful:

$ grep "USB device\|GSM" dmesg
[ 1.268077] usb 1-4: new high speed USB device using ehci_hcd and address 4
[ 1.536043] usb 1-5: new high speed USB device using ehci_hcd and address 5
[ 1.784057] usb 1-8: new high speed USB device using ehci_hcd and address 6
[ 2.160043] usb 2-1: new full speed USB device using uhci_hcd and address 2
[ 2.580045] usb 2-2: new low speed USB device using uhci_hcd and address 3
[ 86.164032] usb 1-4: new high speed USB device using ehci_hcd and address 7
[ 93.028032] usb 1-4: new high speed USB device using ehci_hcd and address 8
[ 93.427410] USB Serial support registered for GSM modem (1-port)
[ 93.428334] option 1-4:1.0: GSM modem (1-port) converter detected
[ 93.430537] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB0
[ 93.430561] option 1-4:1.1: GSM modem (1-port) converter detected
[ 93.432682] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB1
[ 93.432706] option 1-4:1.2: GSM modem (1-port) converter detected
[ 93.433111] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB2
[ 93.433340] option: v0.7.2:USB Driver for GSM modems

Could it be that usb serial support is loaded to late or what triggers "USB Serial support registered for GSM modem (1-port)"?

[Peter Schüller (schueller-p)]

also filed here at usb-modeswitch bugtracking bulletin board
http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?p=5002

[Josua Dietze (digidietze)]

The message that you get is just from the driver which binds to the modem after the mode switch.
It seems that this mode switch is not triggered during boot.

This is the second report of that behaviour I get; unfortunately I can't "re-enact" it on any of my systems.

To state it clearly: there was no change in usb_modeswitch which might cause a differing boot behaviour. I tend to assume that there are differences between versions of udev that are game-changing.

As a first try, edit the file /lib/udev/rules.d/40-usb_modeswitch.rules and change this line:

ACTION!="add", GOTO="modeswitch_rules_end"

to this:

ACTION!="add|change", GOTO="modeswitch_rules_end"

This has reportedly worked on ArchLinux. If you don't get results, you might have to activate udev debug logging. More later.

[Peter Schüller (schueller-p)]

It did not work.

However I activated udev debug logging and you find the syslog and dmesg (bootup took a bit longer than usual) attached.

[Marius B. Kotsbak (mariusko)]

Do you still see this in newer Ubuntu versions?