After installing 12.04 on my vaio laptop everything was OK. But when I disabled the WIFI from the Ubuntu menu the wifi showed an message that it was turned off with the hardware switch.
The weird thing: there is no hardware switch to turn off WIFI, neither does the BIOS have options for disabling the WIFI.
Doing a “rfkill list all”:
0: sony-wifi: Wireless LAN Soft blocked: yes Hard blocked: no 1: sony-bluetooth: Bluetooth Soft blocked: no Hard blocked: no 2: phy0: Wireless LAN Soft blocked: yes Hard blocked: yes 3: hci0: Bluetooth Soft blocked: no Hard blocked: no
After some searching I found a solution:
rfkill unblock wifi
Now your WIFI should work again.