After debugging further, I figured out what was causing the problem. In the driver for the cp210x, there is a line of code in the `.attach` function that calls `usb_reset_device(serial->dev);`. See the source code here: https://github.com/torvalds/linux/blob/master/drivers/usb/serial/cp210x.c#L859
This call to `usb_reset_device` causes the device to be reset just before the second interface is detected. For whatever reason, the reset prevents the second interface from being created in `/dev/`. By simply removing this line, both interfaces are properly detected the first time. Unfortunately, there is a comment above this line that reads "/* cp210x buffers behave strangely unless device is reset */" Therefore, this reset might actually be necessary in order to clear the buffers of the CP210x. In this case, when is the appropriate time to perform a device reset so that both interfaces are properly detected? Thanks, Blake -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
