ACS Failure

[Michal Kazior]

On 18 July 2015 at 15:50, Nathan Royce <naroyce at hotmail.com> wrote:
> config
> *****
> interface=wlan1
> driver=nl80211
> ssid=test
> channel=0
> *****
>
> $ sudo hostapd test.conf
> *****
> Configuration file: test.conf
> ACS: Automatic channel selection started, this may take a bit
> wlan1: interface state UNINITIALIZED->ACS
> wlan1: ACS-STARTED
> ACS: Unable to collect survey data
> ACS: All study options have failed
> Interface initialization failed
> wlan1: interface state ACS->DISABLED
> wlan1: AP-DISABLED
> ACS: Possibly channel configuration is invalid, please report this along with your config file.
> ACS: Failed to start
> wlan1: AP-DISABLED
> hostapd_free_hapd_data: Interface wlan1 wasn't started
> nl80211: deinit ifname=wlan1 disabled_11b_rates=0
> wlan1: interface state DISABLED->DISABLED
> wlan1: interface state DISABLED->DISABLED
> wlan1: AP-DISABLED
> hostapd_free_hapd_data: Interface wlan1 wasn't started
> *****
>
> driver: ath9k_htc
> My understanding is that survey is not implemented, but I was curious about the following output from "event".

Correct. ath9k_htc driver doesn't implement survey dump. I guess the
hardware is capable of providing the data but apparently no one tried
to figure out what registers to use.


> $ iw event
> *****
> wlan1 (phy #1): scan started
> wlan1 (phy #1): scan finished: 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462,
> (repeated 3 more times)
> *****
> With the scan happening, it makes me think maybe survey is implemented.
> On the other hand, "$ iw dev wlan1 survey dump" doesn't output anything in "event".
> It's like maybe hostapd is using a scan as a fallback.

It's not a fallback. hostapd's ACS uses scan to trigger collection of
survey dump of all channels. It does so a few times to limit influence
of bursty traffic.


Micha?