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Date:   Fri, 4 Mar 2022 12:08:18 +0100
From:   Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To:     Jouni Malinen <j@w1.fi>
Cc:     Lorenzo Bianconi <lorenzo@kernel.org>, hostap@lists.infradead.org,
        linux-wireless@vger.kernel.org, nbd@nbd.name,
        ryder.lee@mediatek.com, evelyn.tsai@mediatek.com
Subject: Re: [PATCH 9/9] DFS: introduce radar_background parameter to config
 file
Message-ID: <YiHzIglySEgZpwii@lore-desk>
References: <cover.1640014128.git.lorenzo@kernel.org>
 <3683c678668c4de0ee849974977cf56e64c7162c.1640014128.git.lorenzo@kernel.org>
 <20220303215647.GA33342@w1.fi>
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On Mar 03, Jouni Malinen wrote:
> On Mon, Dec 20, 2021 at 04:48:24PM +0100, Lorenzo Bianconi wrote:
> > Introduce radar_background parameter to configuration file
> > in order to enable/disable background radar/CAC detection.
>=20
> What's the use case for this new parameter and the configuration having
> to explicitly enable this functionality? Is there a reason for not doing
> this in cases where the driver supports this capability? It looks like
> patches 1..8 were enabling this functionality automatically and it is
> only this final patch that makes it depend on a configuration parameter
> (which is default by default).

I added this parameter just to add the capability to disable radar_backgrou=
nd
even if the hw supports it (e.g. for testing/debugging).=20

>=20
> > diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
> > @@ -143,6 +143,13 @@ ssid=3Dtest
> > +# Enable radar/CAC detection through a dedicated background chain avai=
lable on
> > +# some hw. The chain can't be used to transmits or receives frames.
> > +# This feature allows to avoid CAC downtime switching on a different c=
hannel
> > +# during CAC detection on the selected radar channel.
> > +# (default: 0 =3D disabled, 1 =3D enabled)
> > +#radar_background=3D0
>=20
> How would someone writing hostapd configuration know when to enable
> this? Or maybe more importantly, when one should not enable this? Would
> use of that dedicated background chain result in some other capabilities
> getting reduced?

nope, the radar_chain is completely independent from the "data" ones.

>=20
> This is also a bit unclear on what happens if the driver does not
> support this capability and radar_background=3D1 is explicitly set in the
> configuration.

it will not be enabled since we always check WPA_DRIVER_RADAR_BACKGROUND
capability.
Since it is not mandatory, I will drop this patch in the series and always
enable RADAR_BACKGROUND if supported by the hw.

Regards,
Lorenzo

>=20
> --=20
> Jouni Malinen                                            PGP id EFC895FA
>=20

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