No wifi option on Ubuntu (18.04 and 16.04)
Solution 1:
Please start with:
sudo apt update
sudo apt install build-essential git
Now do:
git clone https://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/backport-iwlwifi.git
cd backport-iwlwifi
sudo make
sudo make install
The ‘make’ step takes a few moments; please be patient.
Now, we’ll write a conf file:
sudo -i
echo “options iwlwifi disable_msix=1” >> /etc/modprobe.d/iwlwifi.conf
exit
Reboot and tell us if the wireless is now working.
EDIT: You have compiled the driver for your currently running kernel version only. When Update Manager installs a newer kernel version, after the requested reboot, recompile:
cd backport-iwlwifi
sudo make clean
sudo make
sudo make install
Reboot.
Please retain the files and these instructions for that time.
Solution 2:
I found I had this issue when doing a dual boot of windows 10 and Ubuntu. If I did a hibernate/sleep in windows somehow it would lock up the wifi chip/wifi driver and ubuntu couldn't access it. The solution was to 1) disable fast boot on windows and 2) make sure I "shut down" windows 10 instead of hibernating. Then windows 10 releases the wifi and all versions of ubuntu recognize wifi no problem. Really an infuriating issue, I had hoped to be able to hibernate in windows, switch to Ubuntu, hibernate in ubuntu, switch back, but windows 10 just doesn't play nice :/
edit: here's a link to disabling windows 10 fast startup https://help.uaudio.com/hc/en-us/articles/213195423-How-To-Disable-Fast-Startup-in-Windows-10
edit2: I was also seeing "failed with error -110"... I guess -110 is the windows-is-being-a-jerk error.