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e04e4b6e01
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@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com> Link: https://lore.kernel.org/r/20230330132159.758088-1-jelonek.jonas@gmail.com |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.