[ltp] Re: Sierra Wireless EM7345 4G LTE

Vincent Bernat linux-thinkpad@linux-thinkpad.org
Fri, 04 Jul 2014 18:46:17 +0200

 =E2=9D=A6 18 juin 2014 10:30 +0200, Bj=C3=B8rn Mork <bjorn@mork.no>=C2=A0:

>> After some digging, I have discovered that I can load cdc_ncm with
>> "prefer_mbim=3DY". I get a /dev/cdc-wdm1 device and Modem Manager is able
>> to setup the connection without a problem!
> Yes, I haven't found any way to use this modem in NCM mode, and my
> current theory is that this mode is not supported despite being
> "announced" by the firmware.  This theory is supported by the fact that
> Lenovo provide an MBIM driver for older Windows versions where MBIM
> isn't natively supported.
> So "prefer_mbim=3DY" is definitely the answer for this particular modem.
> I must admit that I did not anticipate a situation like this when adding
> that module option. So that's why it is a global module option instead
> of something you can configure per device.  But I'm hoping that won't
> cause problems for anyone.

I have also noticed that on resume, the cdc_acm module seems to think
there is a problem:

[69937.127857] cdc_mbim 2-4:1.0: cdc-wdm1: USB WDM device
[69937.128063] cdc_mbim 2-4:1.0 wwan0: register 'cdc_mbim' at usb-0000:00:1=
4.0-4, CDC MBIM, 52:ce:08:1e:a7:19
[69937.129148] cdc_acm 2-4:1.2: This device cannot do calls on its own. It =
is not a modem.
[69937.129188] cdc_acm 2-4:1.2: ttyACM0: USB ACM device

I have to unload cdc_acm and cdc_mbim and load cdc_mbim. I'll try to
blacklist cdc_acm to see if there is some enhancement on this front.
# Basic IBM dingbats, some of which will never have a purpose clear
# to mankind
	2.4.0 linux/drivers/char/cp437.uni