The commit 'ath9k_hw: Disable PAPRD for rates with low Tx power' changed
the code that sets the PAPRD rate masks to use only either the HT20 mask
or the HT40 mask. This is wrong, as the hardware can still use HT20 rates
even when configured for HT40, and the operating channel mode does not
affect PAPRD operation.
The register for the HT40 rate mask is applied as a mask on top of the
other registers to selectively disable PAPRD for specific rates on HT40
packets only.
This patch changes the code back to the old behavior which matches the
intended use of these registers. While with current cards this should not
make any practical difference (according to Atheros, the HT20 and HT40
mask should always be equal), it is more correct that way, and maybe
the HT40 mask will be used for some rare corner cases in the future.
Cc: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Target Tx power available in eeprom is for PAPRD. If PAPRD
fails, paprd scale factor needs to be detected from this
target tx power.
Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When the drop in Tx power for a particular mcs rate exceeds
the paprd scale factor, paprd may not work properly. Disable
paprd for any such rates.
Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This helper can be used in multiple places. Also make
it inline returning u8.
Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The EEPROM contains scale factors for the tx power, which define
the range of allowable difference between target power and training
power. If the difference is too big, PA predistortion cannot be used.
For 2.4 GHz there is only one scale factor, for 5 GHz there are
three, depending on the specific frequency range.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The EEPROM PAPRD rate mask fields only contain mask values for actual
rates in the low 25 bits. The upper bits are reserved for tx power
scale values. Add the proper mask definitions and use them before
writing the values to the register.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We are not handling all divide by zero cases in paprd.
Add additional checks for divide by zero cases in papard.
This patch has fixes intended for kernel 2.6.36.
Cc: stable@kernel.org
Signed-off-by: Senthil Balasubramanian <senthilkumar@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The noise floor history buffer is currently not kept per channel, which
can lead to problems when changing channels from a clean channel to a
noisy one. Also when switching from HT20 to HT40, the noise floor
history buffer is full of measurements, but none of them contain data
for the extension channel, which it needs quite a bit of time to recover
from.
This patch puts all the per-channel calibration data into a single data
structure, and gives the the driver control over whether that is used
per-channel or even not used for some channels.
For ath9k_htc, I decided to keep this per-channel in order to avoid
creating regressions.
For ath9k, the data is kept only for the operating channel, which saves
some space. ath9k_hw takes care of wiping old data when the operating
channel or its channel flags change.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Felix Fietkau