Hi!

sys/dev/usb/if_cdce.c has the following comment:

/* * <quote> * The Data Class interface of a networking device shall have a minimum * of two interface settings. The first setting (the default interface * setting) includes no endpoints and therefore no networking traffic is * exchanged whenever the default interface setting is selected. One or * more additional interface settings are used for normal operation, and * therefore each includes a pair of endpoints (one IN, and one OUT) to * exchange network traffic. Select an alternate interface setting to * initialize the network aspects of the device and to enable the * exchange of network traffic. * </quote> * * Some devices, most notably cable modems, include interface settings * that have no IN or OUT endpoint, therefore loop through the list of all * available interface settings looking for one with both IN and OUT * endpoints. */

I've added the loop that follows this comment to umodem.c and found that Nokia E50 returns exactly one additional interface, e.g. usbd_get_no_alts() returns 1. And this interface description has id->bNumEndpoints equal to zero, so there is no IN/OUT endpoint. At all.

Here I'm stuck.