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Date: Thu, 8 Feb 2024 17:44:33 +0100
From: Lorenzo Bianconi <lorenzo@kernel.org>
To: Ben Greear <greearb@candelatech.com>
Cc: Johannes Berg <johannes@sipsolutions.net>,
	linux-wireless@vger.kernel.org
Subject: Re: [PATCH] mac80211: Ensure bss-coloring is always configured
Message-ID: <ZcUE8VU3Nu7vBr3b@lore-desk>
References: <20240130180848.776867-1-greearb@candelatech.com>
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> On 2/8/24 07:55, Lorenzo Bianconi wrote:
> > > On 2/8/24 7:28 AM, Lorenzo Bianconi wrote:
> > > > > On Tue, 2024-01-30 at 10:08 -0800, greearb@candelatech.com wrote:
> > > > > > From: Ben Greear <greearb@candelatech.com>
> > > > > >=20
> > > > > > Old code would not set it to disabled, just assumed that driver
> > > > > > would default to disabled.  Change this to explicitly request
> > > > > > bss color be flushed on initial driver configuration.
> > > > >=20
> > > > > Arguably, the current behaviour is in line with the documentation=
 of
> > > > > BSS_CHANGED_HE_BSS_COLOR ... but I would tend to agree that
> > > > > enabling/disabling coloring should be covered by it as well. Lore=
nzo?
> > > > >=20
> > > > > > And I think the beacon-change logic was slightly wrong, so adju=
st
> > > > > > that as well.
> > > > >=20
> > > > > That's not a great thing for a commit message to say ...
> > > > >=20
> > > > > > Signed-off-by: Ben Greear <greearb@candelatech.com>
> > > > > > ---
> > > > > >    net/mac80211/cfg.c | 10 +++++-----
> > > > > >    1 file changed, 5 insertions(+), 5 deletions(-)
> > > > > >=20
> > > > > > diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
> > > > > > index 1c7fb0959cfd..1a6c6c764cbc 100644
> > > > > > --- a/net/mac80211/cfg.c
> > > > > > +++ b/net/mac80211/cfg.c
> > > > > > @@ -1331,8 +1331,7 @@ static int ieee80211_start_ap(struct wiph=
y *wiphy, struct net_device *dev,
> > > > > >    			      IEEE80211_HE_OPERATION_RTS_THRESHOLD_MASK);
> > > > > >    		changed |=3D BSS_CHANGED_HE_OBSS_PD;
> > > > > > -		if (params->beacon.he_bss_color.enabled)
> > > > > > -			changed |=3D BSS_CHANGED_HE_BSS_COLOR;
> > > > > > +		changed |=3D BSS_CHANGED_HE_BSS_COLOR;
> > > >=20
> > > > I think we should use beacon->he_bss_color_valid here instead of
> > > > params->beacon.he_bss_color.enabled, agree?
> > >=20
> > > Either way, the value changed from un-set/un-known to some value, so =
why not just
> > > mark it changed and flush to the driver?
> >=20
> > IIUC what you mean here, if bss color changes from an un-set/un-known t=
o a
> > configured (valid) value, beacon->he_bss_color_valid will be true
> > (he_bss_color_valid is used to indicate userspace provided a proper col=
or for
> > beacons). What is the difference?
> > The other way around ("undo" some leftover color from a previous run), =
it
> > seems a driver/fw bug, and it must be fixed there. Don't you think?
>=20
> Well, no.  I think the stack should set to known state, thus my original
> patch to do so.
>=20
> But, not worth arguing about as it seems to have no functional difference
> at this point.

I think the second part is fine and should be applied.

Regards,
Lorenzo

>=20
> Thanks,
> Ben
>=20
> >=20
> > Regards,
> > Lorenzo
> >=20
> > >=20
> > > Thanks,
> > > Ben
> > >=20
> > > >=20
> > > > > >    	}
> > > > > >    	if (params->he_cap) {
> > > > > > @@ -1512,6 +1511,7 @@ static int ieee80211_change_beacon(struct=
 wiphy *wiphy, struct net_device *dev,
> > > > > >    	int err;
> > > > > >    	struct ieee80211_bss_conf *link_conf;
> > > > > >    	u64 changed =3D 0;
> > > > > > +	bool color_en;
> > > > > >    	lockdep_assert_wiphy(wiphy);
> > > > > > @@ -1549,9 +1549,9 @@ static int ieee80211_change_beacon(struct=
 wiphy *wiphy, struct net_device *dev,
> > > > > >    		return err;
> > > > > >    	changed |=3D err;
> > > > > > -	if (beacon->he_bss_color_valid &&
> > > > > > -	    beacon->he_bss_color.enabled !=3D link_conf->he_bss_color=
=2Eenabled) {
> > > > > > -		link_conf->he_bss_color.enabled =3D beacon->he_bss_color.ena=
bled;
> > > > > > +	color_en =3D beacon->he_bss_color.enabled && beacon->he_bss_c=
olor_valid;
> > > > > > +	if (color_en !=3D link_conf->he_bss_color.enabled) {
> > > > > > +		link_conf->he_bss_color.enabled =3D color_en;
> > > > > >    		changed |=3D BSS_CHANGED_HE_BSS_COLOR;
> > > > > >    	}
> > > >=20
> > > > this seems fine to me. >
> > > > Regards,
> > > > Lorenzo
> > > >=20
> > > > > >=20
> > > > >=20
> > > > > Not sure how this isn't updating the color itself, Lorenzo?
> > > > >=20
> > > > > johannes
> > > > >=20
> > >=20
> > >=20
> > > --=20
> > > Ben Greear <greearb@candelatech.com>
> > > Candela Technologies Inc  http://www.candelatech.com
>=20
> --=20
> Ben Greear <greearb@candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com
>=20
>=20

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