Building official linux drivers for EM7305

[dl5162]

@rcharolois

Hi all,

I own a Toshiba Portege Laptop (Z30B 12F) with a builtin EM7305 chip. I try to use this broadband access under Linux Ubuntu 16.04, amd64, kernel 4.4.0-21-generic (Ubuntu’s base kernel).

disclaimer: I am quite a newbie in the QMI/MBIM & WWAN card interfaces domain, I might miss some important point. Feel free to correct me.

1. I downloaded and built the drivers as described in document Application Dev Guide v 1.23 (dec 2015)

The document is missing some “modprobe usbserial” before building the driver.

At the end of the procedure, I can see dmesg ( /var/log/syslog) :

[ 4249.253481] GobiNet: 2015-12-08/SWI_2.36
[ 4249.253529] usbcore: registered new interface driver GobiNet
[ 4361.719546] usbcore: deregistering interface driver GobiNet
[ 4378.015448] GobiNet: 2015-12-08/SWI_2.36
[ 4378.015534] usbcore: registered new interface driver GobiNet

But not /dev/ttyUSB* devices appear… What did I miss ?

You need the GobiSerial drvier for /dev/ttyUSB*

GobiNet provides /dev/qcqmi* and wwan* interface pairs.

What is the procedure to force a re-detection ? It’s an embedded chip, I can’t plug/unplug it.

If all you want is to reprobe the device, then unloading and reloading the driver is the easiest method (modprobe -r GobiSerial; modprobe GobiSerial)

You can also do manual unbind/bind using the /sys/bus/usb/drivers/GobiSerial/bind and
/sys/bus/usb/drivers/GobiSerial/unbind sysfs attributes.

If you want to power cycle the modem, then you can sometimes do that using a laptop specific rfkill method. But that is entirely platform specific, and I have no idea what Toshiba does.

2. The vendor/product ID of this chip is 1199:9063. When checking in the official driver source code, nor the serial nor the network seems to support this chip. The last chip supported has ID 1199:9061. Is this related to some mode switching I must opper first ?

My best guess is that 1199:9063 is an ID allocated to Toshiba for use in their OEM version of the EM7305. The “normal” EM7305 device ID is 1199:9041 as far as I know.

3. Is the EM7305 officially supported ? The open source drivers “sierra” and “sierra_net” lacks this chip too.

Those drivers are used for device IDs supporting DirectIP. The relevant mainline drivers for EM7305 are “qcserial” and “qmi_wwan”. But as you’ve discovered: They don’t know the 1199:9063 ID. Simply because noone has reported it yet.

Note that this, as a laptop OEM device, probably is configured for MBIM operation by default. And it should work fine with the mainline “cdc_mbim” driver, since that is class based and does not need to know about specific device IDs.

I added the 1199:9063 vendor/product Ids into the GobiNet and GobiSerial and rebuilt the drivers, but it does not work. Seems the interfaces to open USB ports might have changed ?

I suspect this is because the device is in MBIM only mode by default. Could you post the output of “lsusb -vd 1199:9063” (feel free to remove/obfuscate serial numbers if you like)?

4. This new thread might be related to this one : Steps to get the MC7455 to work under linux which is related to MC7354 not working on Ubuntu.

Thanks for your help, i really need this LTE connection on Ubuntu.

Well, that should work by default, using “cdc_mbim” as driver and ModemManager with libmbim on the userspace side. Anything else is an Ubuntu bug. Ubuntu forums are also probably better at debugging the Ubuntu specific problems…