[ath9k-devel] [4.9.0-rc5] AR9300 calibration problems with antenna selected

[Kalle Valo]

Hi,
I recently tried to select a single antenna on AR9300 and it works for
30 seconds only. The subsequent calibration makes the RX signal level to
drop from the usual -30/-40 dBm to -70/-80 dBm, and the transmission
practically stops.
With the attached patch it works, though selecting the antenna doesn't
seem to have any visible effect, at least with "iw wlanX station dump"
(perhaps it works for TX).
rmmod ath9k
modprobe ath9k
iw dev wlan0 set type ibss
iw phy phyX set antenna 2
ip link set up dev wlan0
iw dev wlan0 set bitrates legacy-2.4 18
iw dev wlan0 ibss join nameXXX freqYYY
ip addr add ZZZ broadcast + dev wlan0
AR9580 Wireless Network Adapter (rev 01), ID 168c:0033, subsystem
19b6:d016.
ieee80211 phy0: Atheros AR9300 Rev:4 mem=0xc0f40000, irq=334
https://routerboard.com/R11e-2HPnD
Linux 4.9.0-rc5.
Is there a better way?
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index e9f32b5..7f17e5d 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -2245,7 +2245,7 @@ static int ath9k_set_antenna(struct ieee80211_hw *hw, u32 tx_ant, u32 rx_ant)
return 0;
/* AR9100 runs into calibration issues if not all rx chains are enabled */
- if (AR_SREV_9100(ah))
+ if (AR_SREV_9100(ah) || AR_SREV_9300(ah))
ah->rxchainmask = 0x7;
else
ah->rxchainmask = fill_chainmask(ah->caps.rx_chainmask, rx_ant);

I'll assume this is an RFC patch. Please resubmit if this is the right
approach.

Patch set to RFC.

[Matthias May]

rmmod ath9k
modprobe ath9k
iw dev wlan0 set type ibss
iw phy phyX set antenna 2

2 is a bad mask. We use bitmap, the valid masks are 1, 3, 7.

Thanks for your response.
I have two antenna connections (and a single antenna). Is it possible to
select the secondary antenna connector only? How?

No this is not really possible.
We have been playing around with this two, three years ago with this.
There are just too many things which rely on chain0
Noise calibration, DFS, Temperature measurement, Spectrum measurement
are just a few of the things I remember which don't work realiably anymore.
See [1] for more.

BR
Matthias

[1]
http://ath9k-devel.ath9k.narkive.com/QZcobwy1/ath9k-deaf-qca9558-when-setting-rxchainmask#post1