On Ubuntu 11.10, I had zero issues with N network detection and speed. I cannot remember whether the old driver was iwlagn or iwlwifi. This was with Ubuntu repository Linux kernel 3.0.0-22.
Upon upgrading to Ubuntu 12.04, iwlwifi is the available driver and while it detects N networks, upon connection, the speed is cripplingly low and DNS look-ups do not occur (impossible to browse). This is with Ubuntu repository Linux kernel 3.2.0-26.
Please note that the 11n_disable flag for the iwlwifi module cannot work for me as I require N network access.
Is there another solution? Perhaps, is there a way to easily patch the new kernel with the old wireless module (just copy-and-paste the iwlagn module into the new kernel source and re-compile)?
Relevant hardware specs: Dell Inspiron N5110 Network Adapter: Intel® Centrino® Wireless-N 1030