I'm using a Xircom PCMCIA ethernet card (xirc2ps_cs) on a Dell Latitude CPx. MULTICAST is enabled (so says ifconfig). However, I can't receive multicast packets unless the interface is switched to PROMISC or ALLMULTI. I do see that the multicast group was joined (via/proc/net/igmp), but no packets arrive.
I've tried different ethernet cards with different drivers (the wavelan for example) and it has the same behavior.
I can duplicate the problem on both 3.1.10 and 3.1.14 using kernel 2.2.14.
Since this doesn't happen using a non-PCMCIA ethernet card, it seems like there is a bug somewhere (either in my configuration or in pcmcia-cs)