Wireless shows up as disabled on a BCM4312 wireless card

Question

I'm using Ubuntu 11.10 (dual booted with Windows Vista) but I'm unable to access internet wirelessly even though I can do so on Vista.

The output for rfkill list all is :

0: brcmwl-0: wireless LAN
         Soft blocked: no
         Hard blocked

The output for lshw -C network is:

  *-network               
       description: Ethernet interface
       product: RTL8111/8168B PCI Express Gigabit Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:08:00.0
       logical name: eth0
       version: 03
       serial: 00:24:e8:c2:20:c9
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl_nic/rtl8168d-1.fw ip=192.168.0.104 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
       resources: irq:46 ioport:3000(size=256) memory:f6004000-f6004fff memory:f6000000-f6003fff memory:f6020000-f603ffff
  *-network DISABLED
       description: Wireless interface
       product: BCM4312 802.11b/g LP-PHY

• Broadcom STA wireless driver is installed, activated, and currently in use
• My laptop is a Dell Vostro 1520

Answer 1

Could you try this command on a terminal?

sudo rmmod dell-laptop

If so, then you're affected by this bug, which is exactly on a Dell Vostro 1520:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/701259

A permanent workaround (try ONLY if the rmmod command does fix the problem) is to run this command on a terminal, to add the module to the blacklist so it doesn't load when the system boots:

echo "blacklist dell-laptop" |sudo tee -a /etc/modprobe.d/blacklist.conf