receive multicast packets on RTL8110SC
 

On my old hardware (VIA chipset internal 100MBit NIC)
i had no problems receiving multicast packets via

setsockopt (fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof (imr))

But on my new board with realtek 8110sc (8169) chip i have a strange effekt:

Mostly i do not receive the packets, "tcpdump eth0[.3]" shows nothing
But in about 1 of 20 tries i get the packets like it should be...
I really don't how this can happen, can someone tell me how i could debug this behaviour ?

Facts: Kernel 2.6.21.5, multicast packets with VLAN tag, but vlan disabled in the NIC driver, vlan eth0.3 configured

mc route set via:
route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0.3


I had vlan enabled in NIC driver before, but got no success..

Update:
OK, further testing revealed, that is has nothing to do with VLAN, effect also happens without.
Looks really like a driver problem for me. I got the r1000 driver from realtek homepage (old driver) compiled, installed, and it worked !!
Also compiled the r8169 from kernel (2.6.21.5) as module, rmmod, insmod and ..
same effect, mostly does not receive the multicast packets.


Thanks
Robert