Ease testing on /dev/cdc-wdmX where X > 0

[Bjørn Mork]

Aleksander Morgado <aleksander at lanedo.com> writes:

>> bjorn at nemi:~$ ls -l /sys/class/net/wwan*
>> lrwxrwxrwx 1 root root 0 Mar 27 09:16 /sys/class/net/wwan0 ->  ../../devices/pci0000:00/0000:00:1d.7/usb2/2-4/2-4:1.7/net/wwan0
>> lrwxrwxrwx 1 root root 0 Mar 27 09:21 /sys/class/net/wwan1 ->  ../../devices/pci0000:00/0000:00:1d.7/usb2/2-1/2-1:1.4/net/wwan1
>> lrwxrwxrwx 1 root root 0 Mar 27 09:22 /sys/class/net/wwan2 ->  ../../devices/pci0000:00/0000:00:1a.7/usb1/1-1/1-1:1.4/net/wwan2
>> bjorn at nemi:~$ ls -l /sys/class/usb/cdc-wdm*
>> lrwxrwxrwx 1 root root 0 Mar 27 09:17 /sys/class/usb/cdc-wdm0 ->  ../../devices/pci0000:00/0000:00:1d.7/usb2/2-4/2-4:1.5/usb/cdc-wdm0
>> lrwxrwxrwx 1 root root 0 Mar 27 09:17 /sys/class/usb/cdc-wdm1 ->  ../../devices/pci0000:00/0000:00:1d.7/usb2/2-4/2-4:1.6/usb/cdc-wdm1
>> lrwxrwxrwx 1 root root 0 Mar 27 09:21 /sys/class/usb/cdc-wdm2 ->  ../../devices/pci0000:00/0000:00:1d.7/usb2/2-1/2-1:1.3/usb/cdc-wdm2
>> lrwxrwxrwx 1 root root 0 Mar 27 09:22 /sys/class/usb/cdc-wdm3 ->  ../../devices/pci0000:00/0000:00:1a.7/usb1/1-1/1-1:1.3/usb/cdc-wdm3
>>
>> Note that the mapping here is
>>
>> wwan0<=>  cdc-wdm0 _and_ cdc-wdm1
>
> Out of the topic of the original email, but... just wondering, are
> those 2 cdm-wdm interfaces in that device fully equivalent, or do they
> have different purposes?

I've never seen any differences in the functionality, but the USB
interface string descriptors indicate different purposes:

 nemi:/tmp# grep . /sys/class/usb/cdc-wdm*/device/interface 
 /sys/class/usb/cdc-wdm0/device/interface:Ericsson F3507g Mobile Broadband Minicard Device Management
 /sys/class/usb/cdc-wdm1/device/interface:Ericsson F3507g Mobile Broadband Minicard PC SC Port

For the record: The same card exports 3 CDC ACM interfaces as well,
where only the GPS one seems special:

 nemi:/tmp# grep . /sys/class/tty/ttyACM*/device/interface 
 /sys/class/tty/ttyACM0/device/interface:Ericsson F3507g Mobile Broadband Minicard Modem
 /sys/class/tty/ttyACM1/device/interface:Ericsson F3507g Mobile Broadband Minicard Data Modem
 /sys/class/tty/ttyACM2/device/interface:Ericsson F3507g Mobile Broadband Minicard GPS Port


So, given that you would normally use cdc_ether for networking, this
card has 4 generic AT command interfaces available for monitoring, SMS,
configuration etc. (excluding the GPS port which may be set up to output
NMEA instead).


Bjørn