From b7c0c238898d200e80487516e2b67aba2a522cc0 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Mon, 10 Dec 2012 14:03:17 +0100 Subject: ath9k_hw: Fix signal strength / channel noise reporting While AR_PHY_CCA_NOM_VAL_* does contain the expected internal noise floor for a chip measured in clean air, it refers to the lowest expected reading. Depending on the frequency, this measurement can vary by about 6db, thus causing a higher reported channel noise and signal strength. Factor in the 6db offset when converting internal noisefloor to channel noise. This patch makes the reported values more accurate for all chips without affecting NF calibration behavior. Signed-off-by: Felix Fietkau Cc: stable@vger.kernel.org Signed-off-by: John W. Linville --- drivers/net/wireless/ath/ath9k/calib.c | 1 + drivers/net/wireless/ath/ath9k/calib.h | 3 +++ 2 files changed, 4 insertions(+) (limited to 'drivers') diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c index f3448a032e6f..1e8508530e98 100644 --- a/drivers/net/wireless/ath/ath9k/calib.c +++ b/drivers/net/wireless/ath/ath9k/calib.c @@ -69,6 +69,7 @@ s16 ath9k_hw_getchan_noise(struct ath_hw *ah, struct ath9k_channel *chan) if (chan && chan->noisefloor) { s8 delta = chan->noisefloor - + ATH9K_NF_CAL_NOISE_THRESH - ath9k_hw_get_default_nf(ah, chan); if (delta > 0) noise += delta; diff --git a/drivers/net/wireless/ath/ath9k/calib.h b/drivers/net/wireless/ath/ath9k/calib.h index 1060c19a5012..60dcb6c22db9 100644 --- a/drivers/net/wireless/ath/ath9k/calib.h +++ b/drivers/net/wireless/ath/ath9k/calib.h @@ -21,6 +21,9 @@ #define AR_PHY_CCA_FILTERWINDOW_LENGTH 5 +/* Internal noise floor can vary by about 6db depending on the frequency */ +#define ATH9K_NF_CAL_NOISE_THRESH 6 + #define NUM_NF_READINGS 6 #define ATH9K_NF_CAL_HIST_MAX 5 -- cgit v1.2.3