There are ath9k wifi cards with open source firmware https://github.com/qca/open-ath9k-htc-firmware
I use these almost exclusively for laptops and routers, I keep ripping Intel wifi cards out of laptops and replacing them with ath9k cards.
Ever since I started doing so things "just work" - no more random disconnects, lockups, need-to-reboot-to-get-wifi-working-again etc.
Technology can be so nice if it's open.
There are ath9k wifi cards with open source firmware https://github.com/qca/open-ath9k-htc-firmware