Jonas Jelonek <jelonek.jonas@xxxxxxxxx> wrote: > Fix incorrect usage of plain rate_idx as index into the max (power) per > rate lookup table. > > For transmit power control (TPC), the ath9k driver maintains internal > tables (in struct ath_hw) to store the max allowed power level per rate. > They are used to limit a given TX-power according to regulatory and user > limits in the TX-path per packet. The tables are filled in a predefined > order, starting with values for CCK + OFDM rates and followed by the > values for MCS rates. Thus, the maximum power levels for MCS do not > start at index 0 in the table but are shifted by a fixed value. > > The TX-power limiting in ath_get_rate_txpower currently does not apply > this shift, thus retrieves the incorrect maximum power level for a given > rate. In particular for MCS rates, the maximum power levels for CCK/OFDM > rates were used, e.g. maximum power for OFDM 0 was used for MCS 0. If > STBC is used, the power is mostly limited to 0 because the STBC table > is zeroed for legacy CCK/OFDM rates. Encountered this during testing of > our work-in-progress TPC per packet for ath9k. > This only has an effect when TPC is enabled in ath9k (tpc_enabled in > struct ath_hw) which defaults to false. In this case it has a > significant impact on the used TX-power, throughput + RSSI. Otherwise > the affected code is just skipped and TX-power is limited with the > hardware registers only. This patch fixes this table lookup. > > Tested on OpenWrt (kernel 5.15.98, but backported ath9k driver) with > small desk setup using ath9k chips AR9280 and AR9580. Cap of TX-power is > working properly for all rates now, throughput and RSSI as expected, > equal to as if TPC was disabled. > Compile-tested with latest 6.3 kernel + allyesconfig. > > Signed-off-by: Jonas Jelonek <jelonek.jonas@xxxxxxxxx> > Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxx> > Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx> Patch applied to ath-next branch of ath.git, thanks. e04e4b6e01e7 wifi: ath9k: fix per-packet TX-power cap for TPC -- https://patchwork.kernel.org/project/linux-wireless/patch/20230330132159.758088-1-jelonek.jonas@xxxxxxxxx/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
