[FS#373] ath9k: high load >10

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Bastian Bittorf (bittorf) 

Attached to Project - LEDE Project
Summary - ath9k: high load >10
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - Supply the following if possible:
 - Device problem occurs on
 - Software versions of LEDE release, packages, etc.
 - Steps to reproduce

with e.g. r2805 on a 'TP-LINK TL-WR1043ND' sometimes i can see:


# top
Mem: 24448K used, 3492K free, 5468K shrd, 448K buff, 6512K cached
CPU:   0% usr 100% sys   0% nic   0% idle   0% io   0% irq   0% sirq
Load average: 8.80 8.48 7.93 6/48 7243
[...]
no task >10%


see the "100% sys" - sometimes load goes >25.
there is no memory pressure and nothing in the log.

when doing 'wifi down' it seems to hang forever.
sometimes it goes away without doing anything.
wifi-mode is adhoc+ap - see the config:


root at exWachturm-drucker:~ :) uci show wireless
wireless.radio0=wifi-device
wireless.radio0.type='mac80211'
wireless.radio0.country='US'
wireless.radio0.frag='off'
wireless.radio0.path='platform/ath9k'
wireless.radio0.htmode='HT20'
wireless.radio0.chanbw='20'
wireless.radio0.channel='5'
wireless.radio0.distance='100'
wireless.radio0.beacon_int='125'
wireless.radio0.txpower='23'
wireless.radio0.hwmode='11ng'

wireless. at wifi-iface[0]=wifi-iface
wireless. at wifi-iface[0].device='radio0'
wireless. at wifi-iface[0].network='wlanadhoc'
wireless. at wifi-iface[0].mode='adhoc'
wireless. at wifi-iface[0].macaddr='f4:ec:38:9d:86:36'
wireless. at wifi-iface[0].mcast_rate='6000'
wireless. at wifi-iface[0].bssid='02:ca:ff:ee:ba:be'
wireless. at wifi-iface[0].ssid='ffintern.2GHz'

wireless. at wifi-iface[1]=wifi-iface
wireless. at wifi-iface[1].device='radio0'
wireless. at wifi-iface[1].network='wlan'
wireless. at wifi-iface[1].encryption='none'
wireless. at wifi-iface[1].mode='ap'
wireless. at wifi-iface[1].macaddr='f6:ec:38:9d:86:36'
wireless. at wifi-iface[1].disabled='0'
wireless. at wifi-iface[1].disassoc_low_ack='1'
wireless. at wifi-iface[1].ssid='weimar.freifunk.net'


More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=373