Quoting Bjørn Mork <bjorn@xxxxxxx>:
snip...
>
> Thanks. The lsusb outputs show that there are no descriptor differences
> between the two modes. The diff you see is only the device address,
> which is a dynamic property and expected to change every time you plug
> in a device.
>
> Unfortunately there is a large number of vendor specific control
> requests addressed to endpoint 0x00 and 0x80, which is odd by itself
> IMHO. These give a number of different values for wValue and wIndes,
> and the meaning is not obvious (too me at least). Some of this is
> obviously switching mode, but it looks like it does so as part of a more
> complex device setup and configuration. So there is no easy way out
> here. We could try replaying the sequence blindly, but I fear that is
> pointless without more understanding.
>
snip...
Well, as I initially posted, this is just a FAQ and workaround for
those who experience this issue. I am not surprised there is a lot of
proprietary stuff going on and it is not a worthwhile reverse
engineering exercise. I do believe a Documentation entry would be
worthwhile so that others who experience this can fix it. A lot of ppl
use M$ for work and this device will get messed up every time.
I will also download the Beceem WiMAX driver and see if it works. I
believe we've spend enough time on this :-)
I've attached a small document for review by maintainers, sierra.txt,
that describes the issue and resolution as of today. I only list
the AC250U device, but hopefully others can add to it as new devices
with this issue are uncovered.
It should be filed under Documentation/usb if accepted.
Thank you for your time!
Peter
August 2013
Driver: sierra
Issue: Devices recognized, but no connection to internet
Root Cause: Device likely set to 4G mode which is unsupported
Resolution: Reset device to use 3G mode using vendor software
Description of Issue:
Users who have a Sierra Wireless (now Netgear) device that operates
in 3G and 4G mode may experience connectivity issues if the device
was placed in 4G mode via vendor software in other Operating Systems.
Currently, the Sierra driver only supports 3G mode. If the device
is in 4G mode, it won't use PPP protocol, but attempt to use WiMAX
which is not currently supported under Linux. As a result, no
connection will be possible.
If using a Sierra (Netgear) device and you experience connectivity
problems, set your device back to 3G mode using vendor sofwtare.
Then reconnect in Linux.
dmesg output will indicate if the Serial device (3G) and/or the
WiMAX device (4G) are detected. If the 4G device is detected, it's
an indication your device is set to 4G mode.
*** Please add to this list ***
Devices currently impacted (see /var/log/messages):
AC250U: 3G Mode Vendor ID: 1199, Product ID: 0301
4G Mode Vendor ID: 198f, Product ID: 0220
Submitted by Peter Hyman
