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Date: Mon, 15 Apr 2024 12:26:44 +0200
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Subject: Re: [PATCH] wifi: mt76: mt7921: avoid undesired changes of the
 preset regulatory domain
From: "Nicolas Escande" <nico.escande@gmail.com>
References: <20240412085357.13756-1-mingyen.hsieh@mediatek.com>
 <D0I1D2J8EB1L.2DPV9W79YKN2C@gmail.com>
 <3e2eb7ab155cbc4819096e32b914d220166a9adb.camel@mediatek.com>
In-Reply-To: <3e2eb7ab155cbc4819096e32b914d220166a9adb.camel@mediatek.com>

On Mon Apr 15, 2024 at 7:53 AM CEST, Mingyen Hsieh (=E8=AC=9D=E6=98=8E=E8=
=AB=BA) wrote:
> On Fri, 2024-04-12 at 11:27 +0200, Nicolas Escande wrote:
> >  	=20
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >  On Fri Apr 12, 2024 at 10:53 AM CEST, Mingyen Hsieh wrote:
> > > From: Leon Yen <leon.yen@mediatek.com>
> > >
> > > Some countries have strict RF restrictions where changing the
> > regulatory
> > > domain dynamically based on the connected AP is not acceptable.
> > > This patch disables Beacon country IE hinting when a valid country
> > code
> > > is set from usersland (e.g., by system using iw or CRDA).
> >=20
> > I always had trouble fully understanding the regulation but isn't the
> > country
> > code IE sole purpose to adapt the regulatory of the client ?=20
> >=20
> Hi Nicolas,
>
> Yes, it is. However, if the users have set the specific country code
> based on their region to the driver, they do not expect the country
> setting to be changed by the country code IE as the AP cannot be
> entirely trusted.

Hi,

In AP mode, I understand that the hardware/firmware (and so user mode to so=
me
extend) is the source of truth about which country/market the product has p=
assed
certification and what not. Thus the country code of an AP should be truste=
d.
If you put an AP from another market at some place, you are responsible for=
 that

But in STA mode the end user should not need to know which regulation follo=
w,
right ? The AP's Country code IE is where the sta gets the final info. So n=
o,
the AP should be trusted, and the user should not (and not the other way ar=
ound)

Of course, I am no an expert on this. I just want to check if there was som=
e
though behind this change. You guys make Wifi chips, you know what you are =
doing

Thanks
>
> Best Regards,
> Yen.
>
> > >
> > > Signed-off-by: Leon Yen <leon.yen@mediatek.com>
> > > Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
> > > ---
> > >  drivers/net/wireless/mediatek/mt76/mt7921/init.c | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > >
> > > diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> > b/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> > > index ef0c721d26e3..3c9a5fcd6924 100644
> > > --- a/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> > > +++ b/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> > > @@ -135,6 +135,13 @@ mt7921_regd_notifier(struct wiphy *wiphy,
> > >  dev->mt76.region =3D request->dfs_region;
> > >  dev->country_ie_env =3D request->country_ie_env;
> > > =20
> > > +if (request->initiator =3D=3D NL80211_REGDOM_SET_BY_USER) {
> > > +if (dev->mt76.alpha2[0] =3D=3D '0' && dev->mt76.alpha2[1] =3D=3D '0'=
)
> > > +wiphy->regulatory_flags &=3D ~REGULATORY_COUNTRY_IE_IGNORE;
> > > +else
> > > +wiphy->regulatory_flags |=3D REGULATORY_COUNTRY_IE_IGNORE;
> > > +}
> > > +
> > >  if (pm->suspended)
> > >  return;
> > > =20
> >=20