Hi Ben, > -----Original Message----- > From: Ben Greear <greearb@xxxxxxxxxxxxxxx> > Sent: Wednesday, March 31, 2021 15:04 > To: Luca Coelho <luca@xxxxxxxxx>; kvalo@xxxxxxxxxxxxxx > Cc: linux-wireless@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 06/12] iwlwifi: mvm: Add support for 6GHz passive scan > > On 3/31/21 2:14 AM, Luca Coelho wrote: > > From: Ilan Peer <ilan.peer@xxxxxxxxx> > > > > When doing scan while 6GHz channels are not enabled, the 6GHz band is > > not scanned. Thus, if there are no APs on the 2GHz and 5GHz bands > > (that will allow discovery of geographic location etc. that would > > allow enabling the 6GHz channels) but there are non collocated APs on > > 6GHz PSC channels these would never be discovered. > > > > To overcome this, FW added support for performing passive UHB scan in > > case no APs were discovered during scan on the 2GHz and 5GHz channels. > > > > Add support for enabling such scan when the following conditions are > > met: > > > > - 6GHz channels are supported but not enabled by regulatory. > > - Station interface is not associated or less than a defined time > > interval passed from the last resume or HW reset flows. > > - At least 4 channels are included in the scan request > > - The scan request includes the widlcard SSID. > > - At least 50 minutes passed from the last 6GHz passive scan. > > Why are you trying so hard to not do passive scans? This seems like it is set > up for all sorts of frustration. > This logic enables a special 'passive' scan which is not directly intended for discovery of APs for connection etc. but for discovery of APs with country information in the beacons/probe responses, so the fw could use this information as an input that might allow it to enable 6GHz channels (which are supported but are disabled). This special scan is intended for cases that the device does not have any other regulatory information that allows it to enable the 6GHz channels. Once these channels are enabled, we use passive scan as needed. We generally try to avoid passive scan on all the 6GHz channels as this is a long flow that takes at least 6 seconds (as there are such 64 channels) and with the discovery mechanisms defined for the 6GHz is not really needed. Hope this clarifies things. Regards, Ilan.
