Return-path: Received: from cora.hrz.tu-chemnitz.de ([134.109.228.40]:55818 "EHLO cora.hrz.tu-chemnitz.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752687Ab3F0Moj (ORCPT ); Thu, 27 Jun 2013 08:44:39 -0400 From: Simon Wunderlich To: Johannes Berg Cc: linux-wireless@vger.kernel.org, Mathias Kretschmer , Simon Wunderlich Subject: [PATCHv4 06/18] cfg80211/mac80211: use reduced txpower for 5 and 10 MHz Date: Thu, 27 Jun 2013 14:44:12 +0200 Message-Id: <1372337064-19254-7-git-send-email-siwu@hrz.tu-chemnitz.de> (sfid-20130627_144541_816457_671E3552) In-Reply-To: <1372337064-19254-1-git-send-email-siwu@hrz.tu-chemnitz.de> References: <1372337064-19254-1-git-send-email-siwu@hrz.tu-chemnitz.de> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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: Simon Wunderlich Signed-off-by: Mathias Kretschmer --- Changes to PATCHv3: * consider max_reg_power, max_power might contain the hardware limit --- include/net/cfg80211.h | 27 +++++++++++++++++++++++++++ net/mac80211/iface.c | 2 +- net/mac80211/main.c | 2 +- net/mac80211/mlme.c | 3 ++- 4 files changed, 31 insertions(+), 3 deletions(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index a0c5e04..cbe7b91 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -461,6 +461,33 @@ ieee80211_chandef_rate_flags(struct cfg80211_chan_def *chandef) } /** + * 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 * * @SURVEY_INFO_NOISE_DBM: noise (in dBm) was filled in diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index a2a8250..093c34a 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -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) diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 626c83c..a1d51af 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -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) { diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 3848b8a..5c1de81 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -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 */ -- 1.7.10.4