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03/11/2011

Gumstix Overo Fire Wifi setup


1. Take a look available wireless signal:

root@overo:~# iwconfig wlan0 essid any
root@overo:~# ifconfig wlan0 up
root@overo:~# iwlist wlan0 scan

2. Edit /etc/network/interfaces to include a section which looks like:

a) Unencypted wifi

Some default builds do not enable any Wifi. You may need to edit /etc/network/interfaces to include a section which looks like:

allow-hotplug wlan0                                                             
auto wlan0
iface wlan0 inet dhcp
pre-up /sbin/iwconfig wlan0 essid any
wireless_mode managed 
 
 
The problem is this setup is not reliable! we're waiting for a solution.

b) WEP encryption

Edit /etc/network/interfaces to have only for wlan0 (don't touch the other entries):

iwconfig wlan0 essid "My Wireless Network"
iwconfig wlan0 key my-hex-key
ifdown wlan0
ifup wlan0

c) WPA encryption

Edit /etc/network/interfaces to have only for wlan0 (don't touch the other entries):

allow-hotplug wlan0
iface wlan0 inet dhcp
pre-up wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant.conf -B
down killall wpa_supplicant

There is an error in the current /etc/network/interfaces as of 2011-09-25. The pre-up line reads:

pre-up wpa_supplicant -Dmarvell -iwlan0 -c/etc/wpa_supplicant.conf -Bw 

The "-Bw" causes a usage message to be dumpted to the screen. Make sure it is just "-B". The -Dmarvell option will yield the message "Unsupported driver 'marvell'. Change it to "-Dwext" as shown above.
My /etc/network/interfaces came this way from the factory, and was also that way in my build from the latest git.

Create /etc/wpa_supplicant.conf containing:


ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=1
ap_scan=1
fast_reauth=1

network={
ssid="add-your-ascii-ssid"
proto=WPA2 # try WPA RSN if you WPA2 fails
key_mgmt=WPA-PSK
pairwise=CCMP TKIP
group=CCMP TKIP
scan_ssid=1
psk="add-your-ascii-passphrase"
priority=10
}

3. Connect to network


To connect to the wireless network when the configuration is done, do the following:

Take down the wireless network (it might already be down, but try to be sure):


# ifdown wlan0
 
Then, bring it up again: 
 
# ifup wlan0
 
4. Power management:
 
Many users have reported issues with wifi data throughput being limited to about 100kB/second. It is theorized this is due to lack of SDIO IRQ support in the OMAP3 MMC driver. A patch is being investigated which reportedly achieves 13Mbps.
Additionally, the driver does not support power management at present. The use of iwconfig power commands such as the following will fail: 

iwconfig wlan0 power on 

Therefore, the wifi module always consumes close to 1 Watt of power when turned on.