Ath9k in 4addr wds mode. After a while the station will break off.
Station connectivity remains. But `ifconfig` cannot see any recv
packet.
wlan0 Link encap:Ethernet HWaddr C8:EE:A6:2E:60:D8
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:17402577 errors:0 dropped:0 overruns:0 frame:0
TX packets:33065526 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1165838023 (1.0 GiB) TX bytes:51166664044 (47.6 GiB)
RX packets count stop increase.
/sys/kernel/debug/ieee80211/phy0/ath9k/recv
PKTS-ALL : 21445223
BYTES-ALL : 2458906640
PKTS-ALL still increase.
