I'm running madwifi on an amd64 Gentoo machine. I have an AR5212 internal card on a Thinkpad Z61m.
Every time I've tried to install madiwifi 0.9.3.1 I've had problems connecting to the wireless access points at my work. With madwifi 0.9.3.1, whenever I scan for APs (either using iwlist ath0 scan or using wpa_supplicant) some weaker access points show up, but the two strongest (my company's - one 802.11a and one 802.11g from the same wireless router) aren't visible. My driver attempts to connect to the local public library's access point (which is the only unsecured access point it can see), but fails because the connection is too weak.
Downgrading to madiwifi 0.9.3 works fine (though that's becoming problematic since the ebuild has been removed from Gentoo Portage) as does booting into Windows XP, so I'm confident it is a driver problem.