[PATCH 5.6 123/254] ath9k: Handle txpower changes even when TPC is disabled

From: Greg Kroah-Hartman
Date: Thu Apr 16 2020 - 10:23:35 EST


From: Remi Pommarel <repk@xxxxxxxxxxxx>

commit 968ae2caad0782db5dbbabb560d3cdefd2945d38 upstream.

When TPC is disabled IEEE80211_CONF_CHANGE_POWER event can be handled to
reconfigure HW's maximum txpower.

This fixes 0dBm txpower setting when user attaches to an interface for
the first time with the following scenario:

ieee80211_do_open()
ath9k_add_interface()
ath9k_set_txpower() /* Set TX power with not yet initialized
sc->hw->conf.power_level */

ieee80211_hw_config() /* Iniatilize sc->hw->conf.power_level and
raise IEEE80211_CONF_CHANGE_POWER */

ath9k_config() /* IEEE80211_CONF_CHANGE_POWER is ignored */

This issue can be reproduced with the following:

$ modprobe -r ath9k
$ modprobe ath9k
$ wpa_supplicant -i wlan0 -c /tmp/wpa.conf &
$ iw dev /* Here TX power is either 0 or 3 depending on RF chain */
$ killall wpa_supplicant
$ iw dev /* TX power goes back to calibrated value and subsequent
calls will be fine */

Fixes: 283dd11994cde ("ath9k: add per-vif TX power capability")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Remi Pommarel <repk@xxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/net/wireless/ath/ath9k/main.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -1457,6 +1457,9 @@ static int ath9k_config(struct ieee80211
ath_chanctx_set_channel(sc, ctx, &hw->conf.chandef);
}

+ if (changed & IEEE80211_CONF_CHANGE_POWER)
+ ath9k_set_txpower(sc, NULL);
+
mutex_unlock(&sc->mutex);
ath9k_ps_restore(sc);