Comment 7 for bug 771758

Lenovo Ideapad U550: wireless was softblocked by acer_wmi. sudo rmmod acer_wmi and adding it to /etc/modprobe.d/blacklist.conf fixed the issue. However, after working for a week (was there a kernel update in proposed?) wireless died again, now with hardblocked state.
Following steps fixed this:
1) removing acer_wmi form /etc/modprobe.d/blacklist.conf
2) rebooting
3) rfkill unblock all
4) sudo rmmod acer_wmi