[PATCH v2 1/2] nl80211: set NL80211_SCAN_FLAG_COLOCATED_6GHZ in scan

[Peer, Ilan]

Hi,

> -----Original Message-----
> From: Johannes Berg <johannes at sipsolutions.net>
> Sent: Wednesday, April 06, 2022 18:47
> To: greearb <greearb at candelatech.com>; Peer, Ilan <ilan.peer at intel.com>;
> hostap at lists.infradead.org
> Cc: Mussai, Tova <tova.mussai at intel.com>; Otcheretianski, Andrei
> <andrei.otcheretianski at intel.com>; Stern, Avraham
> <avraham.stern at intel.com>
> Subject: Re: [PATCH v2 1/2] nl80211: set
> NL80211_SCAN_FLAG_COLOCATED_6GHZ in scan
> 
> On Wed, 2022-04-06 at 08:40 -0700, Ben Greear wrote:
> > On 4/6/22 8:15 AM, Ilan Peer wrote:
> > > From: Tova Mussai <tova.mussai at intel.com>
> > >
> > > Set NL80211_SCAN_FLAG_COLOCATED_6GHZ in the scan params to
> enable
> > > scanning for co-located AP's found in 2.4/5 GHz bands when not
> > > scanning passively. Do so only when collocated scanning is not
> > > disabled by higher layer logic.
> >
> > If I read the double-negatives correctly, this patch enables the new
> > flag by default, and at least in this patch, there is no way to
> > disable that.
> >
> > Should there be a user-configurable in wpa_supplicant.conf to allow
> > enabling/disabling this feature?
> >
> 

I do not see a real reason for this other than for testing purposes. The IEEE802.11 specification direction for discovery on non PSC channels is such that these channels should be scanned only if there is some other indication that there are APs operating on these channels.

> And if not, why didn't we just always set it in the kernel? This still confuses
> me a bit :)
> 

There are cases that the non PSC channels need to be explicitly scanned passively, e.g., for some RRM beacon report use cases. The same might also apply to P2P scanning (not sure if the behavior of P2P full scan is defined on 6GHz).

Regards,

Ilan.