Wireless no longer works after upgrade to 11.10 on Dell XPS L702x

Question

I have a Dell XPS L702x Laptop and after upgrading from 11.04 to 11.10, my wireless no longer works. I'm using a Ethernet cable to get online to ask this question.

> iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.


> lspci -v
...
3:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000
        Subsystem: Intel Corporation Centrino Wireless-N 1000 BGN
        Flags: bus master, fast devsel, latency 0, IRQ 6
        Memory at d7400000 (64-bit, non-prefetchable) [size=8K]
        Capabilities: [c8] Power Management version 3
        Capabilities: [d0] MSI: Enable- Count=1/1 Maskable- 64bit+
        Capabilities: [e0] Express Endpoint, MSI 00
        Capabilities: [100] Advanced Error Reporting
        Capabilities: [140] Device Serial Number 8c-a9-82-ff-ff-89-12-c6
        Kernel modules: iwlagn
...

Anyone know a fix?

(yes, I have tried Fn+F2, to switch on wireless).

Answer 1

I found the issue. It was all my fault :(

In Ubuntu 11.04 I was having stability problems with Wireless N so I created a file called /etc/modprobe.d/iwlagn.conf and put the disable incarnation in it, which is options iwlagn 11n_disable50=1 11n_disable=1 (relevant blog post). It seems 11.10 did not like this hack at all - and was refusing to even recognise wlan with that file in place. I removed this file and rebooted and now wireless works again :) .