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authorFelix Fietkau <nbd@openwrt.org>2013-05-28 18:04:44 +0200
committerJohn W. Linville <linville@tuxdriver.com>2013-05-29 15:22:42 -0400
commit9c8426fc79eef00464d33e774085395cac41d091 (patch)
treeb260e611319bbe1165f8879922c60e0afbb071a1
parentb338f74e33e33616e8fe498b5b09da8a84a7b218 (diff)
ath9k_hw: fix PA predistortion miscalibration
If any bins from the training data are skipped (i != max_index), the calculated compensation curve gets distorted, and the signal will be wildly overamplified. This may be the cause of the reported hardware damage that was caused by PA predistortion (because of which PAPRD was disabled by default). When calculating the x_est, Y, theta values, the use of max_index and i was reversed. i points to the bin index whereas max_index refers to the index of the calculated arrays. Note that PA predistortion is still disabled, it will be re-enabled after it has been properly validated. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--drivers/net/wireless/ath/ath9k/ar9003_paprd.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/drivers/net/wireless/ath/ath9k/ar9003_paprd.c b/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
index 09c1f9da67a..6343cc91953 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
@@ -454,6 +454,8 @@ static bool create_pa_curve(u32 *data_L, u32 *data_U, u32 *pa_table, u16 *gain)
if (accum_cnt <= thresh_accum_cnt)
continue;
+ max_index++;
+
/* sum(tx amplitude) */
accum_tx = ((data_L[i] >> 16) & 0xffff) |
((data_U[i] & 0x7ff) << 16);
@@ -468,20 +470,21 @@ static bool create_pa_curve(u32 *data_L, u32 *data_U, u32 *pa_table, u16 *gain)
accum_tx <<= scale_factor;
accum_rx <<= scale_factor;
- x_est[i + 1] = (((accum_tx + accum_cnt) / accum_cnt) + 32) >>
- scale_factor;
+ x_est[max_index] =
+ (((accum_tx + accum_cnt) / accum_cnt) + 32) >>
+ scale_factor;
- Y[i + 1] = ((((accum_rx + accum_cnt) / accum_cnt) + 32) >>
+ Y[max_index] =
+ ((((accum_rx + accum_cnt) / accum_cnt) + 32) >>
scale_factor) +
- (1 << scale_factor) * max_index + 16;
+ (1 << scale_factor) * i + 16;
if (accum_ang >= (1 << 26))
accum_ang -= 1 << 27;
- theta[i + 1] = ((accum_ang * (1 << scale_factor)) + accum_cnt) /
- accum_cnt;
-
- max_index++;
+ theta[max_index] =
+ ((accum_ang * (1 << scale_factor)) + accum_cnt) /
+ accum_cnt;
}
/*