linux-kernel - [PATCH AUTOSEL 4.18 054/131] ath9k_hw: fix channel maximum power level test

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Date:   Sun, 2 Sep 2018 13:04:09 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Felix Fietkau <nbd@....name>, Kalle Valo <kvalo@...eaurora.org>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 054/131] ath9k_hw: fix channel maximum power
 level test

From: Felix Fietkau <nbd@....name>

[ Upstream commit 461d8a6bb9879b0e619752d040292e67aa06f1d2 ]

The tx power applied by set_txpower is limited by the CTL (conformance
test limit) entries in the EEPROM. These can change based on the user
configured regulatory domain.
Depending on the EEPROM data this can cause the tx power to become too
limited, if the original regdomain CTLs impose lower limits than the CTLs
of the user configured regdomain.

To fix this issue, set the initial channel limits without any CTL
restrictions and only apply the CTL at run time when setting the channel
and the real tx power.

Signed-off-by: Felix Fietkau <nbd@....name>
Signed-off-by: Kalle Valo <kvalo@...eaurora.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/net/wireless/ath/ath9k/hw.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index e60bea4604e4..fcd9d5eeae72 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -2942,16 +2942,19 @@ void ath9k_hw_apply_txpower(struct ath_hw *ah, struct ath9k_channel *chan,
 	struct ath_regulatory *reg = ath9k_hw_regulatory(ah);
 	struct ieee80211_channel *channel;
 	int chan_pwr, new_pwr;
+	u16 ctl = NO_CTL;
 
 	if (!chan)
 		return;
 
+	if (!test)
+		ctl = ath9k_regd_get_ctl(reg, chan);
+
 	channel = chan->chan;
 	chan_pwr = min_t(int, channel->max_power * 2, MAX_RATE_POWER);
 	new_pwr = min_t(int, chan_pwr, reg->power_limit);
 
-	ah->eep_ops->set_txpower(ah, chan,
-				 ath9k_regd_get_ctl(reg, chan),
+	ah->eep_ops->set_txpower(ah, chan, ctl,
 				 get_antenna_gain(ah, chan), new_pwr, test);
 }
 
-- 
2.17.1