MC7700 problem on Linux

IoT Modules MC/EM Series
1

Hi,

so far I used MC8705 and MC7710 on my Linux machine (kernel 2.6.38), and both worked fine with the sierra_net driver (Direct IP) I compiled for this kernel.

for some reason, even though 7710 and 7700 are based on the same chipset, when i plug the MC7700 module in, i’m getting the following error:

[ 5387.476131] usb 2-1: new high speed USB device using ehci_hcd and address 4
[ 5387.609963] usb 2-1: config 1 has an invalid interface number: 8 but max is 3
[ 5387.609972] usb 2-1: config 1 has no interface number 1

lsusb returns the following output:
Bus 002 Device 004: ID 1199:68a2 Sierra Wireless, Inc.

is there a driver update, or a kernel patch?

Roee.

2

problem solved!

I’ve checked the product IDs, and found that:
0x68A2 = QMI
0x68a3 = DIP

which means, my module is configured on QMI which I obviously don’t have driver for.
so, using the following PDF: http://www.szelins.com/download/usermanual/H685_MC7710_from_DIP_to_QMI.pdf I switched the modem mode from QMI to DIP (i did it on windows), and now everything is back to normal :slight_smile:

3

I see that you figured it out, but just wanted to note that these lines are expected, and not really errors:

[ 5387.476131] usb 2-1: new high speed USB device using ehci_hcd and address 4
[ 5387.609963] usb 2-1: config 1 has an invalid interface number: 8 but max is 3
[ 5387.609972] usb 2-1: config 1 has no interface number 1

…not fatal errors in any case. USB interfaces are supposed to be numbered consecutively according to the USB 2.0 spec. But Sierra Wireless (and many other vendors) use fixed numbers to indicate different functions in a composite (i.e. multi-function) USB device. Number 8 is for example used for the QMI/rmnet function.

The Linux kernel sees that there are 4 USB interfaces in total here, and expect them to be numbered 0, 1, 2, 3 instead of 0, 2, 3, 8. So it warns that 8 is higher than max and that 1 is missing. But it is simply a warning and everything continues to work just fine.

I really want to get rid of that warning, but it is formally correct, harmless, and has been there “forever”, so the chances are slim…