I recently got a new Alienware 15 laptop that uses the “Killer Wireless-AC 1525” combo wifi/bluetooth card. When I installed Ubuntu 15.04, everything worked right out the box except for Wifi. After countless hours of research and trial and error, I found this launchpad bug here that has the fix:
Thanks to this fix, it was as easy as just doing a fresh install and then installing this file to get wifi working. Although, the fix requires dkms package installed. Make sure you are either connected with your wired connection to resolve any dependency problems, or download dkms seperately.
Download and install
Download fix and install it with:
sudo dpkg --install ath10k-dkms_1.0_all.deb
Then reboot your system. Once back in, you can verify that wifi is working at the top right. Or, to view all of your detected network cards:
sudo lshw -class network
PS. the fix file was taken from Comment #209. It should work with kernel 3.2 to 4.2