Madwifi drivers for Ubuntu 9.10 (Karmic Koala) or linux kernels 2.6.29 and above.

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: note: previous declaration of 'irqreturn_t' was here
/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c: In function 'ath_attach':
/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c:478: error: 'struct net_device' has no member named 'priv'
/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c:819: error: 'struct net_device' has no member named 'open'
/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c:820: error: 'struct net_device' has no member named 'stop'
/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c:821: error: 'struct net_device' has no member named 'hard_start_xmit'
/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.c:822: error: 'struct net_device' has no member named 'tx_timeout'
.....
.....
.....
make[3]: *** [/home/user/madwifi/madwifi-hal-0.10.5.6/ath/if_ath.o] Error 1
make[2]: *** [/home/user/madwifi/madwifi-hal-0.10.5.6/ath] Error 2
make[1]: *** [_module_/home/user/madwifi/madwifi-hal-0.10.5.6] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.31-14-generic'
make: *** [modules] Error 2

This is due to the fact that there was a change in the kernel headers. The new kernels replaced the old net_device structure with a new one called net_device_ops. It looks like this change exists since kernel 2.6.29 and up.

There currently is no stable release of the madwifi drivers for the new kernerls. But the madwifi project's latest trunk compiles and works fine (at least for me) and I have not noticed any issues yet. This should work with any Linux distribution with a kernel of 2.6.29 and above. To find out your kernel version run:

uname -r

Here is how to get and install it:

1. You can either get the latest trunk from the madwifi website at http://snapshots.madwifi-project.org/madwifi-trunk-current.tar.gz or use the one that worked for me: madwifi-trunk-r4099-20090929.tar.gz

2. Download and uncompress the files:

Provided you downloaded the madwifi-trunk-r4099-20090929.tar.gz file, cd to the directory containing the file. Then gunzip and untar the files:

tar -xvzf madwifi-trunk-r4099-20090929.tar.gz

Cd into the newly created directory:

cd madwifi-trunk-r4099-20090929

3. Install the drivers:

First make sure you have the kernel headers:

sudo apt-get install build-essential

Now compile and install:

sudo make
sudo make install

4. Add the ath_pci module to the kernel:

You need to add a line to the end of the /etc/modules file. The line should read: ath_pci. You can do this with vi of course, but if you don't know the vi editor then it would be much easier to use gedit. So, do:

sudo gedit /etc/modules

Add ath_pci to the end of the file. Here is how my file looks:

# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

lp
sbp2
ath_pci

At this point you can reboot and you should have wireless. You could save yourself a reboot by modprobing the kernel with the ath_pci module like this:

sudo modprobe ath_pci

You should be good to go.