I'm running Gentoo with kernel 4.4 right now.  When I tried upgrading to 4.9, my wireless driver (ath9k) eventually stops working.  On 4.4, the wireless works fine.  When first booting on 4.9, the wireless will work fine for a little while, but eventually the connection starts to slow down and comes to a dead stop.  I'm not sure what the source of the cause is except that it has something to do with kernel version 4.9.dmesg:[  654.808240] wlp3s0: authenticate with XX:XX:XX:XX:XX:XX[  654.825789] wlp3s0: send auth to XX:XX:XX:XX:XX:XX (try 1/3)[  654.827856] wlp3s0: authenticated[  654.829768] wlp3s0: associate with XX:XX:XX:XX:XX:XX (try 1/3)[  654.833827] wlp3s0: RX AssocResp from XX:XX:XX:XX:XX:XX (capab=0x411 status=0 aid=2)[  654.833934] wlp3s0: associated NetworkManager logs:Feb 12 17:04:15 laptop-gentoo NetworkManager[2116]: <warn>  [1486937055.8134] sup-iface[0x1662ab0,wlp3s0]: connection disconnected (reason -4)Feb 12 17:04:15 laptop-gentoo NetworkManager[2116]: <info>  [1486937055.8276] device (wlp3s0): supplicant interface state: completed -> disconnectedFeb 12 17:04:15 laptop-gentoo NetworkManager[2116]: <info>  [1486937055.9196] device (wlp3s0): supplicant interface state: disconnected -> scanningFeb 12 17:04:16 laptop-gentoo NetworkManager[2116]: <info>  [1486937056.9935] device (wlp3s0): supplicant interface state: scanning -> authenticatingFeb 12 17:04:17 laptop-gentoo NetworkManager[2116]: <info>  [1486937057.0005] device (wlp3s0): supplicant interface state: authenticating -> associatedFeb 12 17:04:17 laptop-gentoo NetworkManager[2116]: <info>  [1486937057.0137] device (wlp3s0): supplicant interface state: associated -> 4-way handshakeFeb 12 17:04:17 laptop-gentoo NetworkManager[2116]: <info>  [1486937057.0232] device (wlp3s0): supplicant interface state: 4-way handshake -> completed 
ath9k wireless driver stopped working on Linux kernel 4.9
wifi