ARP failure with EM7430

Sakai, Kouji sakai.koji at
Tue Jun 27 13:16:01 UTC 2017

Hi Bjørn,

Thank you for your reply.

>I don't see how your issue can happen unless you enable ARP again, using
>ifconfig or similar. Or maybe somehting on your system is "helping" you do
>this? The driver does not prevent you from changing these flags to non-working
>settings.  Maybe it should?  But there are so many other ways you can shoot
>yourself in the foot that I just don't see much point in preventing this
>one thing.
>Show us the output of "ifconfig wwp0s20u3i8", and then try "ifconfig -arp
>wwp0s20u3i8" (which is the driver default).

I tried that.

root at thinkpad:~# ifconfig wwp0s20u3i8
wwp0s20u3i8 Link encap:Ethernet  HWaddr f2:56:e0:02:f2:fa  
          inet addr:  Bcast:  Mask:
          inet6 addr: fe80::f056:e0ff:fe02:f2fa/64 Scope:Link
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:230 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:17582 (17.5 KB)

and, as a result of trying "ifconfig wwp0s20u3i8 -arp", 
ARP is stopped and icmp packet is sent!

root at thinkpad:~# tcpdump -i wwp0s20u3i8 
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wwp0s20u3i8, link-type EN10MB (Ethernet), capture size 262144 bytes
18:50:50.291644 IP > ICMP echo request, id 2359, seq 50, length 64
18:50:51.315638 IP > ICMP echo request, id 2359, seq 51, length 64
18:50:52.339651 IP > ICMP echo request, id 2359, seq 52, length 64

But, EM7430 does not seem to transmit the packets. 
Or the packets has not reached EM7430?

root at thinkpad:~# qmicli -d /dev/cdc-wdm0 --wds-get-packet-statistics
[27 Jun 2017, 18:48:37] -Warning ** [/dev/cdc-wdm0] requested auto mode but no MBIM QMUX support available
[/dev/cdc-wdm0] Connection statistics:
	TX packets OK: 0
	RX packets OK: 0
	TX packets dropped: 0
	RX packets dropped: 0
	TX bytes OK: 0
	RX bytes OK: 0

More information about the libqmi-devel mailing list