Arch Linux

zoqaeski

Member

From: /earth/australia/.

Registered: 2009-09-30

Posts: 133

Persistent USB device naming with udev

I've been using a Huawei E160x modem to connect to the internet via pppd based on this wiki article. By and large, it works great, but I've noticed that every now and then (especially after resuming from a suspend or hibernate), the USB serial ports are given different names, so I have to edit the ppp script in order for it to connect to the device.

I don't know if other USB modems are similar, but the Huawei E160x creates four ttyUSB devices, usually numbered 0–3. Only the first one can be used as a modem; I'm yet to figure out what the others do, as they don't seem to answer to ppp or minicom (documentation on minicom is sparse though so I'm probably doing it wrong).

I'm trying to write a rule that will give the first ttyUSB port a persistent name. So far, I've got this:

# /etc/udev/rules.d/99-huawei.rules
# udev rules to make sure my Huawei devices get sensible names
SUBSYSTEM=="usb", ACTION=="add", ATTRS{idVendor}=="12d1", ATTRS{idProduct}=="140c", SYMLINK+="he160x"

But it creates a symlink to "bus/usb/…" , rather than ttyUSB0. Can anyone give some hints on how to set up the rule?