[bkerler]

Hi,

as I had severe issues getting the Samsung Android Modem (/dev/ttyACM0) on the Samsung Galaxy S3 GT-I9300 running, here is why :

Loading the device in linux, it normally defaults to configuration 0 or 1, which will
only support mtp configuration, but not cdc_acm support. This needs switching to configuration 2.

I tried with usb_modeswitch -v04e8 -p6860 -u2 which obviously failed saying that the default configuration is already selected, which confused me a bit. After debugging the source code, I was quickly able to detect what's wrong : the current configuration is detected as 2, although 0/1 is active in fact. I needed to patch the wrong configuration detection in order to enable switching, see attached file

patch.txt

Patch for usb_modeswitch.c

(1.1 KiB) Downloaded 1191 times

, to be patched against the version 2.1.0.

After that, the rest was easy :
first adding the following config to /etc/usb_modeswitch.d/04e8:6860 :

Code: Select all

DefaultVendor=  0x04e8
DefaultProduct= 0x6860

TargetVendor=   0x04e8
TargetProduct=  0x6860

Configuration=2

and adding the following line to /lib/udev/rules.d/40-usb_modeswitch.rules :

Code: Select all

# Samsung Android
ATTRS{idVendor}=="04e8", ATTRS{idProduct}=="6860", RUN+="usb_modeswitch '%b/%k'"

After that, if not already running, do a modprobe cdc_acm and then plug the Samsung Android Device.

To test, use a terminal program of your choice, use as device /dev/ttyACM0 and send "AT+DEVCONFIG?", you should get some device information as answer. Kies protocol should then be also running fine as well.

Hope this will help all other as well struggeling with the modem.

[Josh]

Thanks for the suggestion!

Funny thing is that I'm working on a new release which has the whole configuration query replaced by "libusb_get_configuration". The old function is a left-over from the libusb0 dependency.

The new function is much better as it does not need to ask the device - the value is stored in the device structure already.

[bkerler]

I will be happy to test, as I'm already actively using libusb1