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Date: Fri, 12 Apr 2024 09:38:50 +0200
Message-Id: <D0HZ1KH5VJ8P.2TZZ7NNZXSJA8@gmail.com>
To: "Vasanthakumar Thiagarajan" <quic_vthiagar@quicinc.com>,
 <mbizon@freebox.fr>, "Jeff Johnson" <quic_jjohnson@quicinc.com>, "Ben
 Greear" <greearb@candelatech.com>, "Johannes Berg"
 <johannes@sipsolutions.net>, "Karthikeyan Periyasamy"
 <quic_periyasa@quicinc.com>, <ath12k@lists.infradead.org>
Cc: <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 01/13] wifi: cfg80211: Add provision to advertise
 multiple radio in one wiphy
From: "Nicolas Escande" <nico.escande@gmail.com>
References: <20240328072916.1164195-1-quic_periyasa@quicinc.com>
 <20240328072916.1164195-2-quic_periyasa@quicinc.com>
 <e36599d3269496de59505b36be46f873976f8706.camel@sipsolutions.net>
 <033185b0-f878-a50b-d0d9-57fa79439bdf@quicinc.com>
 <ef6b6a7a4a9d3b01c0eb6abf0991e7e27425e102.camel@sipsolutions.net>
 <80fe5786-f764-455d-ac44-22adf7aeaf94@candelatech.com>
 <31f30c0e318904f3a082c7f213576ceb1f407141.camel@sipsolutions.net>
 <20b56e52-a5e2-70cd-a62a-8c4a3526c2cf@candelatech.com>
 <614bb8a8f1d9174ad7d87cf7636f657cda7b1ef9.camel@sipsolutions.net>
 <aa9e1d54-bb5f-37cc-335f-c9970ab13789@candelatech.com>
 <0cfe990b-182b-4ceb-b5b4-2989fefedb2f@quicinc.com>
 <29f7ecb6d7c208c3614f37616943d5f97bb134d3.camel@freebox.fr>
 <5fc2f2d2-7403-79d2-8909-ddda918ff8d5@quicinc.com>
 <af70ee81e583f58dada3dde87ac335137c4038b0.camel@freebox.fr>
 <6ff353e2-785a-f2ce-8d3b-acc8e79a64cf@quicinc.com>
In-Reply-To: <6ff353e2-785a-f2ce-8d3b-acc8e79a64cf@quicinc.com>

On Fri Apr 12, 2024 at 5:50 AM CEST, Vasanthakumar Thiagarajan wrote:
>
>
> On 4/11/2024 10:09 PM, Maxime Bizon wrote:
> >=20
> > On Thu, 2024-04-11 at 21:56 +0530, Vasanthakumar Thiagarajan wrote:
> >=20
> > Hello,
> >=20
> > Thanks for making it clear,
> >=20
> >=20
> >>> For example, starting a 5Ghz AP in ax-only mode, and at the same
> >>> time
> >>> creating a STA interface on 2.4GHz ?
> >=20
> >> Yes, such use cases continue to be supported in single wiphy mode.
> >=20
> > Understood, but I see some corner cases.
> >=20
> >=20
> > For example, assume two bands AP hardware, 2.4GHz and 5GHz.
> >=20
> > Previously:
> >    - phy0 is 2.4Ghz
> >    - phy1 is 5Ghz
> >    - iw phy phy0 interface create wlan0 type managed
> >    - iw dev wlan0 scan
> >=20
> > =3D> will only scan 2.4Ghz
> >=20
> >=20
> > With single phy approach:
> >    - phy0 is 2.4Ghz + 5Ghz concurrent
> >    - # iw phy phy0 interface create wlan0 type managed
> >    - # iw dev wlan0 scan
> >=20
> > =3D> will scan both bands ?
> >=20
>
> Yes, both the bands will be scanned if freq list is not given
>
> >    - <starting from previous state>
> >    - # iw phy phy0 interface create wlan1 type __ap
> >    - # hostapd -i wlan1 <config>
> >    - # iw dev wlan0 scan
> >=20
> > =3D> what will happen then ?
> >
>
> Scan will be carried out on all the radios including the one on which AP =
interface is=20
> running. Scan with freq list can be used not to disturb the radio of AP i=
nterface.
>
> > > Same goes for hostapd ACS, I assume specifying freqlist becomes
> > mandatory or we can't predict which band the AP will be on ?
> >=20
>
> If no freq list is given, ACS will run through all the bands and select a=
 channel from any=20
> of the bands. But this can be optimized to do ACS and channels selection =
on a particular=20
> band using channellist/freqlist hostapd configurations.
Hello,

And in a (very unlikely) case that there are two underlying radios that can
operate on the same frequencies, how would freqlist enable us to really sel=
ect
the underlying radio ? =20

Thanks
>
> Vasanth