The Problem

I’ve come to notice a quirk in the USB networking capabilities between my basix Gumstix mobo and my Ubuntu laptop. And I’m not the only one who has noticed this quirk. It has also appeared to manifest iteself on the connex boards as well. Maybe we’re not doing something right. But we simply want to have USB networking up and running at boot while a USB cable remains connected between the Gumstix and the laptop. Sure, we could simply pull the USB cable out and reinsert then all is fine. But shoud we really have to do this?

The Solution

The solution is to run /etc/init.d/networking force-reload once the system is finally up and running. Here’s how I implemented it for automation:

Step 1) Modify /etc/network/interfaces to contain the following (use your own IP addresses):

auto usb0
iface usb0 inet static
     address x.x.x.x
     netmask x.x.x.x
     network x.x.x.x
     pre-up /sbin/modprobe g_ether
     post-down /sbin/rmmod g_ether

Step 2) Add the following to /etc/rc.local:

/etc/init.d/networking force-reload

Note: Make sure rc.local is executable!

Step 3) Add a symlink in /etc/rc5.d to point to /etc/rc.local:

ln -s /etc/rc.local /etc/rc5.d/S95ReloadUSB

That should solve it even if you power your Gumstix over USB. If anyone can explain why we don’t need this workaround, I would be very interested in hearing what you have to say.