Re: MM: Non QMI Huawei modems without PPP support?

[Aleksander Morgado <aleksander lanedo com>]

Hey Bjørn,

> 
> following up the recent discussions on libqmi regarding E3276 I am
> wondering if these modems could be supported without too much fuzz by
> ModemManager?
> 
> This is a typical example of such a device (after adding the necessary
> match to the cdc_ncm driver):
> 
> T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  3 Spd=480 MxCh= 0
> D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
> P:  Vendor=12d1 ProdID=1506 Rev= 1.02
> S:  Manufacturer=HUAWEI Technology
> S:  Product=HUAWEI Mobile
> C:* #Ifs= 4 Cfg#= 1 Atr=80 MxPwr=500mA
> I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=02 Prot=12 Driver=option
> E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
> I:  If#= 1 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=02 Prot=16 Driver=cdc_ncm
> E:  Ad=82(I) Atr=03(Int.) MxPS=  64 Ivl=2ms
> I:* If#= 1 Alt= 1 #EPs= 3 Cls=ff(vend.) Sub=02 Prot=16 Driver=cdc_ncm
> E:  Ad=82(I) Atr=03(Int.) MxPS=  64 Ivl=2ms
> E:  Ad=83(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
> I:* If#= 2 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=
> E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> E:  Ad=84(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> I:* If#= 3 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=
> E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> E:  Ad=85(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> 
> 
> So, except for the Mass Storage functions, there is only one serial
> function and one CDC NCM function available.  And according to the
> Windows drvier inf, the serial function is intended for PCUI.  It is
> used to manage the CDC NCM function, and may not support PPP at all(?)
> 
> Ideally ModemManager should use the wwanX interface for data and the
> ttyUSBY device for control, using Huawei vendor specific AT commands to
> initiate and manage the connection.  The known commands specific to
> network device management are AFAIK
> 
> connect:
> AT^NDISDUP=1,1,"apn"
> 
> disconnect:
> AT^NDISDUP=1,0
> 
> check:
> AT^DHCP?
> 
> The last command will return all addresses, but the firmware also
> support running DHCP over the network interface so using these is not
> necessary .  The command is still useful to check whether there is an
> active connection or not.
> 
> Is this something which can be supported relatively easy?
> 
> I do not know how common these devices are, but the E3276 is relatively
> new so there might be an increasing demand for this. Based on the
> Windows driver I expect there are also similar devices with a CDC ECM
> function instead of NCM, but I have not seen any example of those yet.
> So I have so far only submitted a patch for cdc_ncm.
> 
> 

It should not be very difficult to support these modems.

First, we would need a way to guess whether the huawei modem is one of
this kind or not. If this modem replies to "AT+CLAC", please send back
that output. A first try would be to use "AT^NDISDUP=?", assuming that a
proper reply is given by this modem and not by the others. Just
wondering, we may actually be able to decide this looking at the driver
reported?

Are you able to run current git master ModemManager to see how the modem
behaves w.r.t other things like messaging, registration and such? A
debug log would be very helpful, as well as the output of "mmcli -m 0".

Last but not least, if anyone can sponsor a couple of these new devices
for us to test with, that would be best :-)

-- 
Aleksander