After upgrading to the latest Ubuntu version 9.10 I could no longer compile and install the madwifi drivers. Here are the compilation errors I was getting: In file included from /home/user/madwifi/madwifi-hal-0.10.5.6/ath/../net80211/ieee80211_monitor.h:34, from /home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c:75: /home/user/madwifi/madwifi-hal-0.10.5.6/ath/../ath/if_athvar.h:107: error: conflicting types for ‘irqreturn_t’ include/linux/irqreturn.h:16: