Bug 14642
| Summary: | ath9k txpower configuration only takes effect after scan | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Javier Cardona (javier) |
| Component: | network-wireless | Assignee: | Luis Chamberlain (mcgrof) |
| Status: | CLOSED CODE_FIX | ||
| Severity: | low | CC: | ath9k-devel, linville, mcgrof, nenad, sujith, vkthiagu |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.32-rc7-wl | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: | Force tx power change to take effect | ||
Created attachment 23981 [details]
Force tx power change to take effect
Can you please test this patch. It is based on wireless-testing, not sure if it'll apply to 2.6.32-rcx, so may want to try either with bleeding edge compat-wireless or with wireless-testing directly.
So .. any update on tests with the patch? This was tested by another users, going to close this as I just submitted the patch. |
Changing the transmission power while the interface is up and associated has no effect. The following sequence of commands will not affect the output power (verified with a sniffer): # iwconfig wlan0 txpower 20dbm # iwconfig wlan0 wlan0 IEEE 802.11abgn ESSID:"cozyguest" Mode:Managed Frequency:2.462 GHz Access Point: 00:13:10:XX:XX:XX Bit Rate=54 Mb/s Tx-Power=20 dBm ... # iwconfig wlan0 txpower 0dbm # iwconfig wlan0 wlan0 IEEE 802.11abgn ESSID:"cozyguest" Mode:Managed Frequency:2.462 GHz Access Point: 00:13:10:XX:XX:XX Bit Rate=54 Mb/s Tx-Power=0 dBm ... The changes will take effect if the interface is brought down and up or if a scan is issued. Some notes that may be useful to fix this: After mac80211 sets IEEE80211_CONF_CHANGE_POWER the driver updates sc->config.txpowlimit. The new value is sent to the card by ath_update_txpow() which is only called by: 1 364 drivers/net/wireless/ath/ath9k/main.c <<ath_set_channel>> ath_update_txpow(sc); 2 1230 drivers/net/wireless/ath/ath9k/main.c <<ath_radio_enable>> ath_update_txpow(sc); 3 2021 drivers/net/wireless/ath/ath9k/main.c <<ath_reset>> ath_update_txpow(sc); 4 2330 drivers/net/wireless/ath/ath9k/main.c <<ath9k_start>> ath_update_txpow(sc); The new power settings only take effect if one triggers one of these functions, for instance by issuing a scan. Don't have a fix at this time. The obvious fix did not solve the problem: diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index 16bdb1b..b62012e 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -2795,8 +2795,10 @@ static int ath9k_config(struct ieee80211_hw *hw, u32 changed) } skip_chan_change: - if (changed & IEEE80211_CONF_CHANGE_POWER) + if (changed & IEEE80211_CONF_CHANGE_POWER) { sc->config.txpowlimit = 2 * conf->power_level; + ath_update_txpow(sc); + } spin_lock_bh(&sc->wiphy_lock); disable_radio = ath9k_all_wiphys_idle(sc); But issuing a scan after changing the power did: # iwconfig wlan0 txpower 10dbm; iw dev wlan0 scan ( Scanning seems to be the magic word that one must invoke to get things done on ath9k: See also bug 14187 )