EM7455 supported data format


#1

Hi,
which data format does EM7455 module support?
When i tried to set data format to 802-3, qmicli fails with error.
If it supports raw-ip format, then how to get IP configuration for connection.
I am using sprint sim card with sprint firmware on EM7455. I am able to connect to network but not able to get ip.

Thanks,
Prathamesh


#2

Raw IP mode is recommended by the chipset vendor Qualcomm. In Raw IP mode, GobiNet driver is responsible for the Ethernet header process. For outgoing packets, the Ethernet headers are stripped before the driver passes IP packets to the module; For incoming packets, Ethernet headers are added before they are indicated to TCP/IP stack.

If you are able to connect to the network, you may need to start DHCP client to get the network interface configured (assume you are using Sierra Wireless GobiNet and GobiSerial drivers)


#3

The EM7455 supports only raw-ip. For this to work with the upstream kernel driver (qmi_wwan) and qmicli, you’ll need kernel >= 4.4 and then make sure the kernel knows it has to work in raw-ip mode, e.g. using qmicli:
qmicli -d /dev/cdc-wdm0 --set-expected-data-format=raw-ip (this will set some sysfs property to tell the kernel to switch the associated network interface to raw-ip)

Once both the kernel and the device are aligned on the data format, and once you have connected the device normally with qmicli/qmi-network, you will need to either manually configure the IP and routing settings using the values given in qmicli -d /dev/cdc-wdm0 --wds-get-current-settings; or otherwise try DHCP using a DHCP client that supports raw-ip interfaces (the one in busybox? never remember…).

For some context, ModemManager/NetworkManager uses the WDS Get Current Settings message to setup the manual IP and routing settings in normal Linux distributions for this device.


#4

v4.5 actually. (had to look to be sure :slight_smile:)

The v4.4 merge window closed Nov 15 2015, a week or so before I received the MC7455 modules.


#5

Thanks for your inputs. Unfortunately I am using kernel version 4.4 so could not use raw ip mode.
So looks like, have to go ahead with static ip only as mbim doesnt support dynamic ip configuration.


#6

Ah, true, 4.5.
I messed it up because I prepared a Ubuntu 16.04 PPA with 4.4 plus the backported qmi_wwan patches a while ago :slight_smile: