The problem
I have a TP-Link WN722N USB Wifi dongle. Linux Mint picked it up during install and seemed like all was good.
Then the other day, noticed that sometimes WiFi would be flaky like hell
- all I’d get is the password prompt. Turns out that this is a common
problem with USB Wifi. After a few days, the pattern appeared to be a
recurring problem after putting the computer sleep. The fix is easy -
just unload the ath9k_htc before suspending. Edit
/etc/pm/config.d/config (create if needed):
SUSPEND_MODULES="ath9k_htc"