Re: [PATCH net-next v6 0/3] The huawei_cdc_ncm driver / E3276 problem

[Dan Williams <dcbw@redhat.com>]

On Thu, 2014-03-13 at 22:25 +0200, Pasi Kärkkäinen wrote:
> On Mon, Nov 04, 2013 at 09:50:46AM +0100, Bjørn Mork wrote:
> > 
> > [quote Enrico Mioso]
> > 
> > So this is a new, revised, edition of the huawei_cdc_ncm.c driver, which 
> > supports devices resembling the NCM standard, but using it also as a mean 
> > to encapsulate other protocols, as is the case for the Huawei E3131 and
> > E3251 modem devices.
> >
> 
> Hello,
> 
> I'm trying to use Huawei E3276 4G/LTE USB dongle with Linux 3.13.6 kernel,
> and thus i'm using the new huawei_cdc_ncm driver.
> 
> I'm using the /dev/cdc-wdm0 device to send AT commands to it, and that seems to work,
> so the dongle seems like it's connected (also the LED on the dongle suggests it's connected).
> 
> .. the problem is the wwan0 interface (well, udev renames it to wwp0s26u1u5i1) doesn't work.
> Launching a dhcp client on the wwp0s26u1u5i1 doesn't get any IP address.
> 
> Any tips how to troubleshoot this? 

Which AT commands are you using to start the data connection?

I believe Huawei says that DHCP on the network port is only supported if
network port's USB interface has Class 0x2 + SubClass [0x6 | 0xd] +
Protocol 0x0.

Lastly, I think the E3276 has a couple of different "modes" that it can
switch into with usb_modeswitch too, and only some modes expose the
right network interface.  What modeswitch command is getting sent to the
device?

Dan

> I'm seeing "RX errors" listed for the interface in "ifconfig -a" output.. is that normal? 
> 
> The device in question is (ATI command output):
> 
> Manufacturer: huawei
> Model: E3276
> Revision: 21.263.03.00.07
> IMEI: 863XYZXYZXYZXYZ
> +GCAP: +CGSM,+DS,+ES
> 
> Thanks!
> 
> -- Pasi
> 
> 
> > Some precisations are needed however - and I encourage discussion on this: and 
> > that's why I'm sending this message with a broader CC.
> > Merging those patches might change:
> > - the way Modem Manager interacts with those devices
> > - some regressions might be possible if there are some unknown firmware 
> >   variants around (Franko?)
> > 
> > First of all: I observed the behaviours of two devices.
> > Huawei E3131: this device doesn't accept NDIS setup requests unless they're 
> > sent via the embedded AT channel exposed by this driver.
> > So actually we gain funcionality in this case!
> > 
> > The second case, is the Huawei E3251: which works with standard NCM driver, 
> > still exposing an AT embedded channel. Whith this patch set applied, you gain 
> > some funcionality, loosing the ability to catch standard NCM events for now.
> > The device will work in both ways with no problems, but this has to be 
> > acknowledged and discussed. Might be we can develop this driver further to 
> > change this, when more devices are tested.
> > 
> > We where thinking Huawei changed their interfaces on new devices - but probably 
> > this driver only works around a nice firmware bug present in E3131, which 
> > prevented the modem from being used in NDIS mode.
> > 
> > I think committing this is definitely wortth-while, since it will allow for 
> > more Huawei devices to be used without serial connection. Some devices like the 
> > E3251 also, reports some status information only via the embedded AT channel, 
> > at least in my case.
> > Note: I'm not subscribed to any list except the Modem Manager's one, so please 
> > CC me, thanks!!
> > 
> > [/quote]
> > 
> > Enrico Mioso (3):
> >   net: cdc_ncm: Export cdc_ncm_{tx,rx}_fixup functions for re-use
> >   net: huawei_cdc_ncm: Introduce the huawei_cdc_ncm driver
> >   net: cdc_ncm: remove non-standard NCM device IDs
> > 
> >  drivers/net/usb/Kconfig          |   15 +++
> >  drivers/net/usb/Makefile         |    1 +
> >  drivers/net/usb/cdc_ncm.c        |   17 +--
> >  drivers/net/usb/huawei_cdc_ncm.c |  230 ++++++++++++++++++++++++++++++++++++++
> >  include/linux/usb/cdc_ncm.h      |    3 +
> >  5 files changed, 253 insertions(+), 13 deletions(-)
> >  create mode 100644 drivers/net/usb/huawei_cdc_ncm.c
> > 
> > -- 
> > 1.7.10.4
> > 
> > --
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