CSA to DFS channel and ACS not compatible?

[Nicolas Escande]

On Tue Oct 8, 2024 at 5:16 PM CEST, gluedig wrote:
> Hi,
>
> I have 5GHz AP configured with (among other):
> ieee80211h=1
> acs_exclude_dfs=1
> channel=acs_survey
>
> So ACS chooses non-DFS channel on startup (most commonly 36 or 40).
>
> Now, I'm trying to switch channel to ex. 52 which is DFS (and not 
> cleared yet) in my regulatory domain (PL) by doing:
> hostapd_cli chan_switch 10 5260 bandwidth=20
>
[...]

The code probably forbids it and that's why it restarted the AP (and the ACS).
You can start with -d to have more messages and confirm.

Are you sure this is something you really wish to do ? You need to clear a DFS
channel before switching to it (so wait between 1 & 10 min). So doing CSA (which
is supposed to be done in a matter of a few seconds max) to such a channel,
would mean telling a STA to go somewhere the AP is not. Seems weird.