Comment 169 for bug 640100

It looks like it is a wireless device module issue. I'm using 11.04 with out-of-the-box kernel 2.6.38-8-generic .

Patching up /usr/lib/pm-utils/sleep.d/55NetworkManager
with :

case "$1" in
 hibernate|suspend)
  suspend_nm
                modprobe -r ath9k
  ;;
 thaw|resume)
  modprobe ath9k
  resume_nm
  ;;
 *) exit $NA
  ;;
esac

solved this, and my N150 is now returning from suspend.