Re: [PATCH] mac80211: fix recalc_radar hwconf sync problem

[Zefir Kurtisi <zefir.kurtisi@neratec.com>]

On 04/04/2013 08:22 PM, Simon Wunderlich wrote:
> [...]
> 
> So the patch does not resolve the problem for you? I've checked it again with
> a little printk in ath9ks config function.
> 
> With the patch the radar_enabled flag gets disabled when changing the channel (5500 -> 5200).
> If I don't apply the patch, it stays enabled. I did the same thing (start hostapd on
> channel 5500, wait for CAC, echo 1 > /sys/kernel/debug/ieee80211/phy0/ath9k/simulate_radar).
> 
> Maybe I'm missing something?
> 
Hi Simon,

here is how to reproduce (assuming you are using the patches for DFS testing on
ath9k posted yesterday).

1) enable DFS log output at ath9k
echo 1 > /sys/kernel/debug/ieee80211/phy0/ath9k/debug

2) run hostapd on DFS channel, my config is as follows
interface=wlan3
driver=nl80211
ssid=testap
hw_mode=a
channel=108
wmm_enabled=1
ieee80211d=1
ieee80211h=1
country_code=DE
wpa_group_rekey=300
wpa_gmk_rekey=640
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
wpa_passphrase=testtest

The log output I see is:
Apr 5 11:44:00: [ 335.210749] IPv6: ADDRCONF(NETDEV_UP): wlan3: link is not ready
Apr 5 11:44:00: [ 335.221152] ath: phy0: DFS enabled at freq 5540
Apr 5 11:44:04: [ 339.234487] ath: phy0: DFS enabled at freq 5540
Apr 5 11:44:04: [ 339.260298] ath: phy0: DFS enabled at freq 5540
Apr 5 11:44:04: [ 339.262750] ath: phy0: DFS enabled at freq 5540
Apr 5 11:44:04: [ 339.262786] IPv6: ADDRCONF(NETDEV_CHANGE): wlan3: link becomes ready

So we passed the (shortened to 4s) CAC and AP is operating.

3) fire radar
echo 1 > /sys/kernel/debug/ieee80211/phy0/ath9k/simulate_radar

I see:
Apr 5 11:44:25: [  360.294667] ath: phy0: DFS enabled at freq 5540
Apr 5 11:44:25: [  360.297217] ath: phy0: DFS enabled at freq 5240


The 'DFS enabled ...' message is print if ath9k_config() is called with
hw->conf.radar_enabled, which should never happen for freq 5240.


I wish I had time to learn using ftrace to track it down... As said before, it is
not critical for ath9k, but might be a hint to something going wrong above.


Thanks,
Zefir