Wireless not working on Dell XPS 17 after installing 12.04

Before you do all that, check your BIOS settings.

I have the same machine and, every once in a while, it will report that wireless is disabled by hardware switch.

It happens only when I suspend the machine while plugged into an ethernet wired connection and then wake it up expecting to use wireless only.

The wireless "button" above the keyboard will not turn it back on, so I have to go into BIOS to re-enable it. Save, reboot, enable wireless in Network Connections and everything's back to normal.

I've got a Dell XPS 17 (l702x) with an n-1000 I'd like to get working under Ubuntu 12.04 (once I install it). So, lending heavily from this post:

The fix seems to involve downgrading the n-1000's firmware.

Please downgrade the firmware with iwlwifi-1000-ucode-128.50.3.1.tgz (for ease, save it to your desktop). You can right-click it and select 'Extract' or issue the following at a terminal prompt:

tar xzvf ~/Desktop/iwlwifi-1000-ucode-128.50.3.1.tgz 

Again, in the terminal, back up the current firmware:

sudo mv /lib/firmware/iwlwifi-1000-5.ucode /lib/firmware/iwlwifi-1000-5.bak

Now copy over the downloaded firmware:

cd Desktop/iwlwifi-1000-ucode-128.50.3.1/
cp iwlwifi-1000-3.ucode iwlwifi-1000-5.ucode
sudo cp iwlwifi-1000-5.ucode /lib/firmware
sudo modprobe -r iwlagn
sudo modprobe iwlagn

Now let's see what happened under the hood:

dmesg | tail -n20

This has been tested and confirmed in the original post, and is said to be a permanent fix (i.e. is still working after a reboot).

best of luck!