ath9k: fix max noise floor threshold

commit 2ee0a07028d2cde6e131b73f029dae2b93c50f3a upstream.

Currently the maximum noise floor limit is set as too high (-60dB). The
assumption of having a higher threshold limit is that it would help
de-sensitize the receiver (reduce phy errors) from continuous
interference. But when we have a bursty interference where there are
collisions and then free air time and if the receiver is desensitized too
much, it will miss the normal packets too. Lets make use of chips
specific min, nom and max limits always. This patch helps to improve the
connection stability in congested networks.

Cc: Paul Stewart <pstew@google.com>
Tested-by: Gary Morain <gmorain@google.com>
Signed-off-by: Madhan Jaganathan <madhanj@qca.qualcomm.com>
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
[bwh: Backported to 3.0/3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index a1250c586e40884989a853845e1c68230434f6c2..1f2f97f6038fd4c546883963ba5b0f84be6263e8 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -19,7 +19,6 @@
 
 /* Common calibration code */
 
-#define ATH9K_NF_TOO_HIGH      -60
 
 static int16_t ath9k_hw_get_nf_hist_mid(int16_t *nfCalBuffer)
 {
@@ -335,10 +334,10 @@ static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
                        "NF calibrated [%s] [chain %d] is %d\n",
                        (i >= 3 ? "ext" : "ctl"), i % 3, nf[i]);
 
-               if (nf[i] > ATH9K_NF_TOO_HIGH) {
+               if (nf[i] > limit->max) {
                        ath_dbg(common, ATH_DBG_CALIBRATE,
                                "NF[%d] (%d) > MAX (%d), correcting to MAX\n",
-                               i, nf[i], ATH9K_NF_TOO_HIGH);
+                               i, nf[i], limit->max);
                        nf[i] = limit->max;
                } else if (nf[i] < limit->min) {
                        ath_dbg(common, ATH_DBG_CALIBRATE,