Now it’s almost automatically attached as modem after insertion and people have been contributing to list of device-and-target device after mode-switching (find it as /usr/share/usb_modeswitch/configPack.tar.gz). At least for Raspberry Pi (RPi), I have one device list from August 2012 when playing around with XBian 0.8.3 and one from May 2012 in when using Raspbian Wheezy (2012-08-16).

Huawei E220 requires no mode-switch from vendor-product ID 12d1:1003 to function as modem

There is still wrapper for udev in /lib/udev/rules.d/40-usb_modeswitch.rule and my Huawei E153 HSDPA stick recognized and switched successfully as shown:

usb_modeswitch: switching device 12d1:1446 on 001/005
...
logger: usb_modeswitch: switched to 12d1:14ac on 001/006

But I didn’t get there in the first place. Because of USB power problem (detailed in previous post), I used to plug USB devices before powering up so that I could use Y-cable injected by separate power source without powered USB-hub. It turned out that if I had plugged the USB before powering up the RPi the mode-switching didn’t occur.

The HSDPA USB modem used is Huawei E153 appearing in lsusb with vendor-product ID 12d1:1446. Using aforementioned XBian and target device 12d1:140c (suggested in Santinoli’s post), I arbitrarily succeeded to switch to modem and dial internet with pppd.

[root]$ usb_modeswitch -v 12d1 -p 1446 -P 140c

(I placed Santinoli’s config in /etc/usb_modeswitch.conf)
This wasn’t stable however (also note that XBian consumed CPU above 50% for xbmc).

Later I find out that it will automatically switch to 12d1:14ac instead when plugged in after RPi is up. However, since it also won’t switch if plugged before power-up, I also try to mode-switch manually using config file found inside /usr/share/usb_modeswitch/configPack.tar.gz archive named 12d1:1446.

[root]$ usb_modeswitch -v 12d1 -p 1446 -c 12d1\:1446

It doesn’t seem to work. Modification to something close to my previous config also fails. Hence, consistent result only occurs if the stick is plugged in after RPi up. Then I decide to use USB-hub (also detailed in previous post) to tackle power issue (it will reboot anyway if you plug in without adequate powering). However, after successful mode-switch what’s being reported in eLinux Wiki often happens: it slows down, try lsub command for example.

Currently I give up the idea of using that modem and choose older Huawei E220:

1. No usb_modeswitch. Driver attached directly by the kernel as option.ko device (this device has been on the list for long)
2. Stable. No slowing down

The E153 modem itself has been implemented to stream video using the higher ARM type BeagleBoard-xM without significant stability issue (check my YouTube demo). It mode-switched when powering up Ubuntu on the Beagle.

$ modprobe -v usbserial vendor=0x05c6 product=0x0015

or (2) usb-modeswitch, (3) Matthias Urlichs initially wrote option.c driver as a way to insert USB modem as kernel module.

This driver exists because the “normal” serial driver doesn’t work too well
with GSM modems. Issues:
- data loss — one single Receive URB is not nearly enough
- nonstandard flow (Option devices) control
- controlling the baud rate doesn’t make sense

Most modems will be successfully attached with this driver, appearing in one of the typical /dev/ttyUSB0 to /dev/ttyUSB2. The product ID 0x0015 for GSM modem compiled here is a Qualcomm (vendor ID 0x05c6) OEM modem I received from Embest DevKit8500D order. There are more than one form factor when searching for its images on Google. Closest one we have in Indonesia is ADVAN DT8-HT bundled in Telkomsel Flash.

Qualcomm 05c6:0015 from Indonesian operator

I’m compiling it for the Beagleboard xM Rev C running Ubuntu Oneiric (installed in this post). A quick look gives:

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 005: ID 05c6:0015 Qualcomm, Inc.

The above 0x0015 product ID doesn’t exist inside option.c of linux kernel 3.0.0-12 source. Adding this to series of existing Qualcomm modems gives:

635
636
637

	{ USB_DEVICE(QUALCOMM_VENDOR_ID, 0x6000)}, /* ZTE AC8700 */
	{ USB_DEVICE(QUALCOMM_VENDOR_ID, 0x6613)}, /* Onda H600/ZTE MF330 */
	{ USB_DEVICE(QUALCOMM_VENDOR_ID, 0x0015)}, /* Qualcomm no brand */

The include also needs usb-wwan.h from that kernel source. Copy them both under /usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/. For other include files, install:

1. linux-headers-3.0.0-12_3.0.0-12.20_all.deb
2. linux-image-3.0.0-12-omap_3.0.0-12.20_armel.deb

and create this link as root

1
2

$ cd /usr/src/linux-headers-3.0.6-x3/include/
$ ln -s /usr/src/linux-headers-3.0.0-12/arch/arm/mach-versatile/include/mach mach

After removing the old one (pointed to build -> /build/buildd/linux-3.0), create a link inside /lib/modules/3.0.6-x3 named build pointing to:

build -> /usr/src/linux-headers-3.0.6-x3

Modify the original Makefile to contain only rule for option.o

obj-m			+= option.o

and then build the driver

$ make -C /lib/modules/3.0.6-x3/build/ M=/usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/
make: Entering directory `/usr/src/linux-headers-3.0.6-x3'
  LD      /usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/built-in.o
  CC [M]  /usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/option.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/option.mod.o
  LD [M]  /usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/option.ko
make: Leaving directory `/usr/src/linux-headers-3.0.6-x3`

Copy the build and deploy

$ cp /usr/src/linux-headers-3.0.6-x3/drivers/usb/serial/option.ko /lib/modules/3.0.6-x3/kernel/drivers/usb/serial/
$ depmod -a

Now syslog will show the following lines if the modem is inserted:

kernel:[ 4790.229888] usb 1-2.5: GSM modem (1-port) converter now attached to ttyUSB0
kernel:[ 4790.237121] option 1-2.5:1.0: GSM modem (1-port) converter detected
kernel:[ 4790.238250] usb 1-2.5: GSM modem (1-port) converter now attached to ttyUSB1
kernel:[ 4790.240142] option 1-2.5:1.1: GSM modem (1-port) converter detected
kernel:[ 4790.241210] usb 1-2.5: GSM modem (1-port) converter now attached to ttyUSB2
mtp-probe: checking bus 1, device 9: "/sys/devices/platform/usbhs-omap.0/ehci-omap.0/usb1/1-2/1-2.5"
mtp-probe: bus: 1, device: 9 was not an MTP device
kernel:[ 4791.227294] scsi 2:0:0:0: Direct-Access     Qualcomm MMC Storage      2.31 PQ: 0 ANSI: 2
kernel:[ 4791.232238] sd 2:0:0:0: Attached scsi generic sg0 type 0
kernel:[ 4791.246887] sd 2:0:0:0: [sda] Attached SCSI removable disk