hostapd "Could not connect to kernel driver" with madwifi-ng

Ryan Castellucci ryan.castellucci at
Thu Apr 20 16:21:12 EDT 2006

On 3/31/06, Ryan Castellucci <ryan.castellucci at> wrote:
> I'm using hostapd 0.5.2 compiled with madwifi-ng r1475, and I get the
> following when I attempt ot that hostapd:
> # hostapd -dddd /rw/etc/hostapd-ath0.conf
> Configuration file: /rw/etc/hostapd-ath0.conf
> madwifi_set_iface_flags: dev_up=0
> Using interface ath0 with hwaddr 00:02:6f:20:fa:82 and ssid 'test-ath0'
> SIOCGIWRANGE: WE(compiled)=19 WE(source)=13 enc_capa=0x0
> Flushing old station entries
> madwifi_sta_deauth: addr=ff:ff:ff:ff:ff:ff reason_code=3
> ioctl[IEEE80211_IOCTL_SETMLME]: Invalid argument
> Could not connect to kernel driver.
> Deauthenticate all stations
> madwifi_set_iface_flags: dev_up=0

So, I've found the problem.

On line 1198 of driver_madwifi.c
madwifi_set_iface_flags(drv, 0);      /* mark down during setup */

The interface gets taken down. Then, hostapd tries to run a deauth
command. This is not possible when the device is down, so madwifi
returns invalid argument. If the above line of code is commented out,
hostapd starts.
Ryan Castellucci

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