Re: [PATCH] wifi: mac80211: skip reconfiguration when the last emulated chanctx goes
From: Johannes Berg
Date: Thu Sep 03 2026 - 13:37:38 EST
On Sat, 2026-08-29 at 13:15 +0300, Nerijus Bendžiūnas wrote:
> Drivers without native channel contexts get the emulated ops, and
> ieee80211_emulate_remove_chanctx() reconfigures the hardware with no
> context left, which ieee80211_calc_hw_conf_chan() turns into a channel
> change to the default channel. A monitor-mode retune releases its
> context before using the next one, so every retune costs the driver two
> channel changes: one to the default channel and one to the channel that
> was asked for. Nothing is on the air without a context and the next
> context sets the channel, so drop that reconfiguration; the radar flag
> is still cleared for the next configuration to carry.
>
> On an AR9271 (ath9k_htc), where every channel change is a full reset
> over USB, hopping across the 13 standard 2.4 GHz channels with an
> unmodified driver showed 2006 drv_config CHANGE_CHANNEL calls for 1000
> hops with the reconfiguration and 1006 without, a median hop of 123.5 ms
> against 92.0 ms (p95 183 ms against 105 ms), and 99.1% against 98.3% of
> injected frames delivered on a second card.
>
> Signed-off-by: Nerijus Bendžiūnas <nerijus.bendziunas@xxxxxxxxx>
You're expected to disclose LLM usage.
https://www.kernel.org/doc/html/latest/process/coding-assistants.html
And please clean up the wordering everywhere before submitting again.
johannes