Huawei me906s-158

[Bjørn Mork]

Andreas Fett <andreas.fett at secunet.com> writes:
> On 08/03/16 19:05, Bjørn Mork wrote:
>> But one simple change to test is this patch:
>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/net/usb/cdc_ncm.c?id=48906f62c96cc2cd35753e59310cb70eb08cc6a5
>> 
>> Which will be in v4.5, and hopefully asserted stable releases too soon, if
>> you don't want to do your own patching.  FWIW, this should not make any
>> difference at all.  And I don't think it will. But I have been surprised
>> before...
>
> I had (somewhat limited) success.
>
> Applying the patch to 4.4.2 did not help... So I build a 4.5-rc7+ kernel
> directly from Linus' tree (I checked that it contained your patch).
>
> I also placed the configuration switch in an udev rule that triggers as
> soon as the xhci module is loaded and the devices on that bus appear.
>
> In previous attempts I had a rule which disabled runtime power
> management for all devices. I had to disable that one too.

Interesting.  You are sure this made a difference?  It should not of
course.  There is definitely something odd going on with this modem. 

> I still have to load the mbim_module manually and sometimes I'm able to
> "talk" to it. I have no clue which factors lead to success or failure here.

Huh?  Why do you need to load cdc_mbim manually?  Doesn't it autoload
when the modem is switched to the MBIM configuration? Or is the probe
failing at this time?

> Attached you will find logs of an attempt where I could use mbimcli
> and afterwards started the modem manager and did a successful connect.
>
> Unfortunately when I configure the wwan0 interface with ip and routes
> from the bearer I'm still not able to do a successful ping...

Strange. There are no BULK IN data received at all from the modem.  This
is quite unusual.  Even when things doesn't completely work, there is
often a packet or two from the modem.  But this one is silent.

Well, a couple of more things to try out if you are able to connect
again:

1) move the NDP

With a v4.5 kernel you will have a "ndp_to_end" sysfs attribute.  Try
toggling it on and see if that makes any difference:

 echo Y >/sys/class/net/wwan0/cdc_ncm/ndp_to_end

You can do this after connecting if you want to.  The driver will enable
it immediately for the rest of the session.


2) DHCP

You should also try using a DHCP client instead of manual IP
configuration.  Some firmwares can be a bit difficult about this,
although I don't think we have seen that with MBIM yet.  Mostly worth
trying because it is easy to test. Not really believing it will work :)



Bjørn