Hi!

This is really a bug report about OpenWRT failing to register appropriate device nodes, making USB modems needlessly difficult to use.
It's a regression in  CHAOS CALMER (15.05, r46767) compared to Attitude Adjustment.

Main problem: GSM connection using the option driver never autostarts.

The modem in question is an Ovation 935, which needs usb_modeswitch. It normally creates 2 serial devices - usually /dev/ttyUSB0 and /dev/ttyUSB1.
When it's plugged in, however, only the /dev/ttyUSB1 is present, and it's obviously not connected despite network config present.

Every time I want to use it, I need to do:

rmmod option
insmod option

Then the network starts.

dmesg of the appearance:

[   21.480000] usb 1-1: USB disconnect, device number 2
[   21.930000] usb 1-1: new high-speed USB device number 3 using ehci-platform
[   22.530000] option 1-1:1.0: GSM modem (1-port) converter detected
[   22.530000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[   22.540000] option 1-1:1.1: GSM modem (1-port) converter detected
[   22.550000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[   22.960000] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[   22.970000] option 1-1:1.0: device disconnected
---- rmmod ----
[  197.570000] usbserial: USB Serial deregistering driver GSM modem (1-port)
[  197.580000] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[  197.590000] usbcore: deregistering interface driver option
[  197.590000] option 1-1:1.1: device disconnected
---- insmod ----
[  200.970000] usbcore: registered new interface driver option
[  200.970000] usbserial: USB Serial support registered for GSM modem (1-port)
[  200.980000] option 1-1:1.0: GSM modem (1-port) converter detected
[  200.990000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[  201.000000] option 1-1:1.1: GSM modem (1-port) converter detected
[  201.000000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1

I do not have the time to set up the toolchain, but I can help with testing of the images. It would be great if this worked like it dif before.