wireless: reg: restore previous behaviour of chan->max_power calculations

commit eccc068e8e84c8fe997115629925e0422a98e4de
Author: Hong Wu <Hong.Wu@dspg.com>
Date:   Wed Jan 11 20:33:39 2012 +0200

    wireless: Save original maximum regulatory transmission power for the calucation of the local maximum transmit pow

changed the way we calculate chan->max_power as min(chan->max_power,
chan->max_reg_power). That broke rt2x00 (and perhaps some other
drivers) that do not set chan->max_power. It is not so easy to fix this
problem correctly in rt2x00.

According to commit eccc068e8 changelog, change claim only to save
maximum regulatory power - changing setting of chan->max_power was side
effect. This patch restore previous calculations of chan->max_power and
do not touch chan->max_reg_power.

Cc: stable@vger.kernel.org # 3.4+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -891,7 +891,21 @@ static void handle_channel(struct wiphy *wiphy,
 	chan->max_antenna_gain = min(chan->orig_mag,
 		(int) MBI_TO_DBI(power_rule->max_antenna_gain));
 	chan->max_reg_power = (int) MBM_TO_DBM(power_rule->max_eirp);
-	chan->max_power = min(chan->max_power, chan->max_reg_power);
+	if (chan->orig_mpwr) {
+		/*
+		 * Devices that have their own custom regulatory domain
+		 * but also use WIPHY_FLAG_STRICT_REGULATORY will follow the
+		 * passed country IE power settings.
+		 */
+		if (initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE &&
+		    wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY &&
+		    wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY)
+			chan->max_power = chan->max_reg_power;
+		else
+			chan->max_power = min(chan->orig_mpwr,
+					      chan->max_reg_power);
+	} else
+		chan->max_power = chan->max_reg_power;
 }
 
 static void handle_band(struct wiphy *wiphy,