[PATCH] ath9k: fix per-packet tx power configuration

[PATCH] ath9k: fix per-packet tx power configuration

[Lorenzo Bianconi]

Do not use ieee80211_vif pointer in ath_get_rate_txpower() since it has been
overwritten by setup_frame_info() and it will result in a corrupted tx power
configuration. Set per-packet tx power in setup_frame_info() according to
current vif tx power.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
---
 drivers/net/wireless/ath/ath9k/xmit.c | 52 +++++++++++++++++------------------
 1 file changed, 25 insertions(+), 27 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 0acd079..3ad79bb 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1103,28 +1103,14 @@ static u8 ath_get_rate_txpower(struct ath_softc *sc, struct ath_buf *bf,
 	struct sk_buff *skb;
 	struct ath_frame_info *fi;
 	struct ieee80211_tx_info *info;
-	struct ieee80211_vif *vif;
 	struct ath_hw *ah = sc->sc_ah;
 
 	if (sc->tx99_state || !ah->tpc_enabled)
 		return MAX_RATE_POWER;
 
 	skb = bf->bf_mpdu;
-	info = IEEE80211_SKB_CB(skb);
-	vif = info->control.vif;
-
-	if (!vif) {
-		max_power = sc->cur_chan->cur_txpower;
-		goto out;
-	}
-
-	if (vif->bss_conf.txpower_type != NL80211_TX_POWER_LIMITED) {
-		max_power = min_t(u8, sc->cur_chan->cur_txpower,
-				  2 * vif->bss_conf.txpower);
-		goto out;
-	}
-
 	fi = get_frame_info(skb);
+	info = IEEE80211_SKB_CB(skb);
 
 	if (!AR_SREV_9300_20_OR_LATER(ah)) {
 		int txpower = fi->tx_power;
@@ -1161,25 +1147,26 @@ static u8 ath_get_rate_txpower(struct ath_softc *sc, struct ath_buf *bf,
 			txpower -= 2;
 
 		txpower = max(txpower, 0);
-		max_power = min_t(u8, ah->tx_power[rateidx],
-				  2 * vif->bss_conf.txpower);
-		max_power = min_t(u8, max_power, txpower);
+		max_power = min_t(u8, ah->tx_power[rateidx], txpower);
+
+		/* XXX: clamp minimum TX power at 1 for AR9160 since if
+		 * max_power is set to 0, frames are transmitted at max
+		 * TX power
+		 */
+		if (!max_power && !AR_SREV_9280_20_OR_LATER(ah))
+			max_power = 1;
 	} else if (!bf->bf_state.bfs_paprd) {
 		if (rateidx < 8 && (info->flags & IEEE80211_TX_CTL_STBC))
 			max_power = min_t(u8, ah->tx_power_stbc[rateidx],
-					  2 * vif->bss_conf.txpower);
+					  fi->tx_power);
 		else
 			max_power = min_t(u8, ah->tx_power[rateidx],
-					  2 * vif->bss_conf.txpower);
-		max_power = min(max_power, fi->tx_power);
+					  fi->tx_power);
 	} else {
 		max_power = ah->paprd_training_power;
 	}
-out:
-	/* XXX: clamp minimum TX power at 1 for AR9160 since if max_power
-	 * is set to 0, frames are transmitted at max TX power
-	 */
-	return (!max_power && !AR_SREV_9280_20_OR_LATER(ah)) ? 1 : max_power;
+
+	return max_power;
 }
 
 static void ath_buf_set_rate(struct ath_softc *sc, struct ath_buf *bf,
@@ -2129,6 +2116,7 @@ static void setup_frame_info(struct ieee80211_hw *hw,
 	struct ath_node *an = NULL;
 	enum ath9k_key_type keytype;
 	bool short_preamble = false;
+	u8 txpower;
 
 	/*
 	 * We check if Short Preamble is needed for the CTS rate by
@@ -2145,6 +2133,16 @@ static void setup_frame_info(struct ieee80211_hw *hw,
 	if (sta)
 		an = (struct ath_node *) sta->drv_priv;
 
+	if (tx_info->control.vif) {
+		struct ieee80211_vif *vif = tx_info->control.vif;
+
+		txpower = 2 * vif->bss_conf.txpower;
+	} else {
+		struct ath_softc *sc = hw->priv;
+
+		txpower = sc->cur_chan->cur_txpower;
+	}
+
 	memset(fi, 0, sizeof(*fi));
 	fi->txq = -1;
 	if (hw_key)
@@ -2155,7 +2153,7 @@ static void setup_frame_info(struct ieee80211_hw *hw,
 		fi->keyix = ATH9K_TXKEYIX_INVALID;
 	fi->keytype = keytype;
 	fi->framelen = framelen;
-	fi->tx_power = MAX_RATE_POWER;
+	fi->tx_power = txpower;
 
 	if (!rate)
 		return;
-- 
2.1.0

Re: [PATCH] ath9k: fix per-packet tx power configuration

[Kalle Valo]

Lorenzo Bianconi <lorenzo.bianconi83@gmail.com> writes:

> Do not use ieee80211_vif pointer in ath_get_rate_txpower() since it has been
> overwritten by setup_frame_info() and it will result in a corrupted tx power
> configuration. Set per-packet tx power in setup_frame_info() according to
> current vif tx power.
>
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>

I'm planning to send this fix to 4.1, is that ok?

-- 
Kalle Valo

Re: [PATCH] ath9k: fix per-packet tx power configuration

[Lorenzo Bianconi]

>> Do not use ieee80211_vif pointer in ath_get_rate_txpower() since it has been
>> overwritten by setup_frame_info() and it will result in a corrupted tx power
>> configuration. Set per-packet tx power in setup_frame_info() according to
>> current vif tx power.
>>
>> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
>
> I'm planning to send this fix to 4.1, is that ok?
>

I agree. That patch has been tested on an urban noisy link and the RX
signal strength is solid. The throughput is stable as well. The patch
hopefully fixes the issue reported in the commit
'c09396eb8e5a8df668174993c6400763022b2466 - ath9k: disable TPC support
again (for now)'

Best regards,
Lorenzo

> --
> Kalle Valo



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Re: ath9k: fix per-packet tx power configuration

[Kalle Valo]

> Do not use ieee80211_vif pointer in ath_get_rate_txpower() since it has been
> overwritten by setup_frame_info() and it will result in a corrupted tx power
> configuration. Set per-packet tx power in setup_frame_info() according to
> current vif tx power.
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>

Thanks, applied to wireless-drivers.git.

Kalle Valo