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Date: Thu, 8 Feb 2024 16:55:53 +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: <ZcT5ibvlnU0ivp5s@lore-desk>
References: <20240130180848.776867-1-greearb@candelatech.com>
 <7c2721f79c1d6c0aa914db4f4d6148c8efce4b85.camel@sipsolutions.net>
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> 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. Lorenzo?
> > >=20
> > > > And I think the beacon-change logic was slightly wrong, so adjust
> > > > 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 wiphy *w=
iphy, 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?

IIUC what you mean here, if bss color changes from an un-set/un-known to a
configured (valid) value, beacon->he_bss_color_valid will be true
(he_bss_color_valid is used to indicate userspace provided a proper color f=
or
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?

Regards,
Lorenzo

>=20
> Thanks,
> Ben
>=20
> >=20
> > > >   	}
> > > >   	if (params->he_cap) {
> > > > @@ -1512,6 +1511,7 @@ static int ieee80211_change_beacon(struct wip=
hy *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 wip=
hy *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.ena=
bled) {
> > > > -		link_conf->he_bss_color.enabled =3D beacon->he_bss_color.enabled;
> > > > +	color_en =3D beacon->he_bss_color.enabled && beacon->he_bss_color=
_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

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