Ubuntu – Wifi problem after suspend resume – solution

In 14.04 and 14.10 versions there is such problem in some devices. The solution can be different. But in 99% cases
the problem appears due to one of these two reasons: wpa_suplicant bug, wifi sleep bug.
Let’s go:
1. Try to restart network manager via terminal:

sudo restart network-manager

If it helps and after this command wifi started working, then add this command to autorun file. Run this command:

sudo gedit /etc/pm/sleep.d

In editor window paste this:

case "${1}" in
    resume|thaw)
        service network-manager restart;;
esac

2. May be it is wpa_suplicant problem. Run this command

sudo pkill -f wpa_supplicant

If it helps, then add this to autorun file:

sudo gedit /etc/pm/wpa_supplicant

In editor window paste this:

#!/bin/sh
case "$1" in
 resume)
   killall wpa_supplicant       
 ;;
esac

3. May be it is nmcli nm sleep problem. Then try this solution.

4. If none of above helped, try this solution from Ubuntu Forums