FWIW,

multicast/v6 is still broken on zd1211rw on 2.6.22.1 based Fedora 7 
kernel (2.6.22.1-33.fc7).

On Thu, 28 Jun 2007, Pekka Savola wrote:

On Fedora 7 (kernel 2.6.21-1.3228.fc7, based on 2.6.21.5), my 
zd1211rw_mac80211 WLAN USB stick and multicast/v6 no longer works. On Fedora 
6 (kernel 2.6.20, no mac80211) it was OK.

I get "wlan0: duplicate address detected!" on dmesg when the kernel is trying 
to autoconfigure a global address.

I suppose this is caused by the IPv6 stack seeing my own ICMPv6 neighbor 
solicitation and thinking it was originated by someone else:

08:46:21.762807 00:02:72:5b:dc:28 > 33:33:ff:5b:dc:28, ethertype IPv6 
(0x86dd), length 78: (hlim 255, next-header: ICMPv6 (58), length: 24) :: > 
ff02::1:ff5b:dc28: [icmp6 sum ok] ICMP6, neighbor solicitation, length 24, 
who has 2001:708:10:90:202:72ff:fe5b:dc28

Strangely, the same error isn't printed with the link-local address which 
uses the same EUI-64.

z1211rw Wiki seems to imply that this might be an issue in generic mac80211 
code:

http://www.linuxwireless.org/en/users/Drivers/zd1211rw/mac80211Issues

It'd be nice to get this fixed.  Or has it already been?

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings