Recently I had to use a laptop for a course I was doing. This Fujisu Siemens Amilo Li 2727 laptop came with Windows Vista pre-installed. Since the installed OS didn’t matter for the course I installed the latest Ubuntu which is 9.04 (Jaunty). All worked well except for the wireless card (Atheros Communications Inc. AR242x 802.11abg Wireless PCI Express Adapter (rev 04)). The network applet says “Wireless is disabled”. The ath5k driver for the wireless card is being correctly initialised, as you can see:

[ 12.170260] ath5k_pci 0000:08:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18 [ 12.170274] ath5k_pci 0000:08:00.0: setting latency timer to 64 [ 12.170439] ath5k_pci 0000:08:00.0: registered as 'phy0' [ 12.355693] ath5k phy0: Atheros AR2425 chip found (MAC: 0xe2, PHY: 0x70) [ 264.864848] ath5k phy0: noise floor calibration timeout (2442MHz)

You can also use the following command to see if the device is blocked (not tuned on!):

$ sudo rfkill list 0: acer-wireless: Wireless LAN Soft blocked: no Hard blocked: no 1: phy0: Wireless LAN Soft blocked: no Hard blocked: yes

It appears that the wireless card is enabled but not activated, so you’ll need to turn it on. Using Windows you use the Fn-F1 key combination to activate the wireless card, but this doesn’t work with Linux. The easiest way to get wireless going is by activating a kernel module called acer_wmi. As soon as you execute the following line you’ll notice the wireless led will light up. There are other ways, but this is by far the most easy and elegant way to do it.

$ sudo modprobe acer_wmi

The wireless card is now active! Wait a moment and you’ll see wireless networks appear in the NetworkManager if you’re in range. Just for the record I am using Ubuntu kernel 2.6.28-11-generic at the moment of writing.

To make this solution last on a reboot, you’ll have to add the module name ‘acer_wmi’ to ‘/etc/modules’.

$ echo "acer_wmi" | sudo tee /etc/modules

30 Apr 2010: I can confirm this work-around also works for Ubuntu 10.04 LTS (Lucid).
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