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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@kernel.org>
To:     Hancheng Yang <hyang@freebox.fr>, kvalo@codeaurora.org,
        Johannes Berg <johannes@sipsolutions.net>,
        Jouni Malinen <j@w1.fi>
Cc:     linux-wireless@vger.kernel.org, Hancheng Yang <hyang@freebox.fr>
Subject: Re: [PATCH] ath9k: reset survey of current channel after a scan
 started
In-Reply-To: <87wmxtby1g.fsf@toke.dk>
References: <20230817092900.361270-1-hyang@freebox.fr> <87wmxtby1g.fsf@toke.dk>
Date:   Fri, 01 Sep 2023 12:43:05 +0200
Message-ID: <87v8cutbra.fsf@toke.dk>
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Toke H=C3=B8iland-J=C3=B8rgensen <toke@kernel.org> writes:

> Hancheng Yang <hyang@freebox.fr> writes:
>
>> In the `ath_set_channel()` function, we only reset surveys that are not =
from the current channel.
>> This leads to the accumulation of survey data for the current channel in=
definitely.
>> Log of hostapd:
>> [2023-08-17 11:21:51] ACS: Survey analysis for channel 1 (2412 MHz)
>> [2023-08-17 11:21:51] ACS: 1: min_nf=3D-90 interference_factor=3D0.56983=
3 nf=3D-89 time=3D36194 busy=3D20908 rx=3D16200
>> [2023-08-17 11:21:51] ACS: 2: min_nf=3D-90 interference_factor=3D0.57201=
8 nf=3D-89 time=3D36539 busy=3D21183 rx=3D16425
>> [2023-08-17 11:21:51] ACS: 3: min_nf=3D-90 interference_factor=3D0.57431=
1 nf=3D-90 time=3D36885 busy=3D21464 rx=3D16659
>> [2023-08-17 11:21:51] ACS: 4: min_nf=3D-90 interference_factor=3D0.5773 =
nf=3D-89 time=3D37231 busy=3D21772 rx=3D16924
>> [2023-08-17 11:21:51] ACS: 5: min_nf=3D-90 interference_factor=3D0.58010=
8 nf=3D-89 time=3D37578 busy=3D22076 rx=3D17189
>>
>>
>> This may not be the most optimal approach, as we want the ACS to rely on=
 the most recent survey.
>> So, reset the survey data for the current channel at the start of each s=
can.
>>
>> Or there's better approach?
>
> Johannes, Jouni, any thoughts? :)

Ping?

>>
>> Signed-off-by: Hancheng Yang <hyang@freebox.fr>
>> ---
>>  drivers/net/wireless/ath/ath9k/main.c | 15 +++++++++++++++
>>  1 file changed, 15 insertions(+)
>>
>> diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireles=
s/ath/ath9k/main.c
>> index fa5a87f021e2..3e4a711c96bb 100644
>> --- a/drivers/net/wireless/ath/ath9k/main.c
>> +++ b/drivers/net/wireless/ath/ath9k/main.c
>> @@ -2382,7 +2382,22 @@ static void ath9k_sw_scan_start(struct ieee80211_=
hw *hw,
>>  {
>>  	struct ath_softc *sc =3D hw->priv;
>>  	struct ath_common *common =3D ath9k_hw_common(sc->sc_ah);
>> +	struct cfg80211_chan_def *chandef =3D &sc->cur_chan->chandef;
>> +	struct ieee80211_channel *chan =3D chandef->chan;
>> +	int pos =3D chan->hw_value;
>>  	set_bit(ATH_OP_SCANNING, &common->op_flags);
>> +
>> +	/* Reset current survey */
>> +	if (!sc->cur_chan->offchannel) {
>> +		if (sc->cur_survey !=3D &sc->survey[pos]) {
>> +			if (sc->cur_survey)
>> +				sc->cur_survey->filled &=3D ~SURVEY_INFO_IN_USE;
>> +			sc->cur_survey =3D &sc->survey[pos];
>> +		}
>> +
>> +		memset(sc->cur_survey, 0, sizeof(struct survey_info));
>> +		sc->cur_survey->filled |=3D SURVEY_INFO_IN_USE;
>> +	}
>>  }
>>=20=20
>>  static void ath9k_sw_scan_complete(struct ieee80211_hw *hw,
>> --=20
>> 2.34.1