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Commit 0430c883 authored by Simon Wunderlich's avatar Simon Wunderlich Committed by Johannes Berg
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cfg80211/mac80211: use reduced txpower for 5 and 10 MHz 



Some regulations (like germany, but also FCC) express their transmission
power limit in dBm/MHz or mW/MHz. To cope with that and be on the safe
side, reduce the maximum power to half (10 MHz) or quarter (5 MHz)
when operating on these reduced bandwidth channels.

Signed-off-by: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarMathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
parent 74608aca

include/net/cfg80211.h

+27 −0
Original line number Diff line number Diff line
@@ -460,6 +460,33 @@ ieee80211_chandef_rate_flags(struct cfg80211_chan_def *chandef) 
	return 0;

}



/**

 * ieee80211_chandef_max_power - maximum transmission power for the chandef

 *

 * In some regulations, the transmit power may depend on the configured channel

 * bandwidth which may be defined as dBm/MHz. This function returns the actual

 * max_power for non-standard (20 MHz) channels.

 *

 * @chandef: channel definition for the channel

 *

 * Returns: maximum allowed transmission power in dBm for the chandef

 */

static inline int

ieee80211_chandef_max_power(struct cfg80211_chan_def *chandef)

{

	switch (chandef->width) {

	case NL80211_CHAN_WIDTH_5:

		return min(chandef->chan->max_reg_power - 6,

			   chandef->chan->max_power);

	case NL80211_CHAN_WIDTH_10:

		return min(chandef->chan->max_reg_power - 3,

			   chandef->chan->max_power);

	default:

		break;

	}

	return chandef->chan->max_power;

}



/**

 * enum survey_info_flags - survey information flags

 *

net/mac80211/iface.c

+1 −1
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata) 
		return false;

	}



	power = chanctx_conf->def.chan->max_power;

	power = ieee80211_chandef_max_power(&chanctx_conf->def);

	rcu_read_unlock();



	if (sdata->user_power_level != IEEE80211_UNSET_POWER_LEVEL)

net/mac80211/main.c

+1 −1
Original line number Diff line number Diff line
@@ -151,7 +151,7 @@ static u32 ieee80211_hw_conf_chan(struct ieee80211_local *local) 
		changed |= IEEE80211_CONF_CHANGE_SMPS;

	}



	power = chandef.chan->max_power;

	power = ieee80211_chandef_max_power(&chandef);



	rcu_read_lock();

	list_for_each_entry_rcu(sdata, &local->interfaces, list) {

net/mac80211/mlme.c

+2 −1
Original line number Diff line number Diff line
@@ -747,7 +747,8 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata) 
		*pos++ = WLAN_EID_PWR_CAPABILITY;

		*pos++ = 2;

		*pos++ = 0; /* min tx power */

		*pos++ = chan->max_power; /* max tx power */

		 /* max tx power */

		*pos++ = ieee80211_chandef_max_power(&chanctx_conf->def);



		/* 2. supported channels */

		/* TODO: get this in reg domain format */