Latest patch by Stephen Hemminger on bugs.kernel.com solved the problem for me, I'm using a custom 2.6.18.1 kernel on dapper.
See also here http://bugzilla.kernel.org/show_bug.cgi?id=6839 ** Attachment added: "Yukon FE ram buffer initialization" http://librarian.launchpad.net/4922170/sky2.patch -- sky2 driver freezing system after ifdown and ifup https://launchpad.net/bugs/38865 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
