If you need the D-link DWA-547 working under linux in

• station-mode (so connected to an access point): the ath9k-driver is good for that
• hostap-mode (so card can be used as an AccessPoint itself): the madwifi-driver could do it, but i did not get it working
• monitor-mode (so you can see other networks): the ath9k-driver does that
• adhoc-mode: the ath9k-driver is good for that

• D-link DWA-547

# lspci -vv
...
00:0b.0 Network controller: Atheros Communications Inc. AR5416 802.11abgn Wireless PCI Adapter (rev 01)
        Subsystem: D-Link System Inc Device 3a6b
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 168, Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 19
        Region 0: Memory at bd800000 (32-bit, non-prefetchable) [size=64K]
        Capabilities: [40] #80 [0000]
        Kernel driver in use: ath9k
        Kernel modules: ath9k

• debian unstable/udev with kernel 2.6.29-2 loads ath9k module
• debian unstables old linux-image-2.6.26 doesnt contain the ath9k driver

• madwifi is the older, unfree driver, but usually provides all modes one could want (all 4)
• problems to compile madwifi on kernels >2.6.28, you should use oder kernels or just use AdHoc mode
• http://madwifi-project.org/wiki/Compatibility/D-Link - lists DWA-547 as supported
• madwifi 0.9.4 cannot be compiled with this:

  CC [M]  /home/chris/madwifi-0.9.4/net80211/ieee80211_power.o
/home/chris/madwifi-0.9.4/net80211/ieee80211_power.c: In function 'ieee80211_pwrsave':
/home/chris/madwifi-0.9.4/net80211/ieee80211_power.c:240: error: implicit declaration of function '__skb_append'
make[3]: *** [/home/chris/madwifi-0.9.4/net80211/ieee80211_power.o] Error 1
make[2]: *** [/home/chris/madwifi-0.9.4/net80211] Error 2
make[1]: *** [_module_/home/chris/madwifi-0.9.4] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.26-1-686'
make: *** [modules] Error 2

• checking out current madwifi with svn co http://svn.madwifi-project.org/madwifi/trunk madwifi and compiling this works

# compile, modprobe ath_pci
wlanconfig ath0 destroy
wlanconfig ath0 create wlandev wifi0 wlanmode ap
ifconfig ath0 10.0.7.5 netmask 0xffffff00 broadcase 10.0.7.255
ip r d default
ip r a default via 10.0.7.1
hostapd -B /etc/hostapd/hostapd.conf.works4
/etc/init.d/dhcpd start

• ath9k is the open driver, the way to go - but as of today the host-ap mode is not yet usable
• http://wireless.kernel.org/en/users/Drivers/ath5k has some usage-instructions that also apply to ath9k drivers
• http://wireless.kernel.org/en/users/Drivers/ath9k - lists supported wlan-hardware
• http://wireless.kernel.org/en/users/Download - instructions on getting and installing ath9k, but as of 2.6.29 its in the vanilla kernel

modprobe ath9k
iwconfig wlan0 essid fluxcoil mode managed
wpa_supplicant ..
dhclient wlan0

• could only get b/g mode to work (so 3mbyte/sec throughput), wasnt able to use n mode

# be aware, just using WEP in this example, you know this is almost no encryption at all!
modprobe ath9k
iwconfig wlan0 mode ad-hoc
iwconfig wlan0 key 1234567890 # the wep-key
iwconfig wlan0 channel auto
ifconfig wlan0 up
iwconfig wlan0 essid testernet
ifconfig wlan0 192.168.0.1 netmask 0xffffff00 
iwconfig wlan0

Not usable for the AR5416 chip used in the DWA-547 card. Earlier somethimes ath5k was loaded automatically, its useless for the d-link dwa-547.

ndiswrapper makes the windows-driver usable, havent tried it. Should make station-mode usable but since this is provided by the ath9k-driver that one should be used.