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From:   Aaron Komisar <aaron.komisar@tandemg.com>
To:     "peter.oh@eero.com" <peter.oh@eero.com>
CC:     "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: [PATCH v3] mac80211: fix scan blocked on DFS channels in ETSI domains
Thread-Topic: [PATCH v3] mac80211: fix scan blocked on DFS channels in ETSI
 domains
Thread-Index: AQHVeSmOSAENpyhoVE6RI/+qs7ypzKdHoGQAgADyMIA=
Date:   Thu, 3 Oct 2019 08:13:38 +0000
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On 10/2/19 5:46 PM, Peter Oh wrote:
>On 10/2/19 6:59 AM, Aaron Komisar wrote:
>> In non-ETSI reg domains scan is blocked when operating channel is a DFS =
ch.
>> For ETSI domains, however, once DFS channel is marked as available afer
>> the CAC, this channel will remain available even after leaving this chan=
nel.
>> Therefore a new CAC will not be required when scan is done.
>>
>> In cfg80211 scan is not blocked for ETSI reg domains.
>> This patch enables scan in mac80211 as well when operating channel is a =
radar
>> channel for ETSI reg domains (unless CAC is in progress).
>>
>This is not the right approach to solve the problem.
>
>The real reason of scan failure is because mac80211 checks if it's DFS
>channel, but it doesn't check if CAC is done or not.

The problem is that scan request is blocked in ETSI reg domains. In non-ETS=
I
reg domains the behavior is fine.

cfg80211 blocks scan in non-ETSI reg domains and allows leaving the channel
in ETSI reg domains. I think that if we add a function in mac80211, which
checks if we can leave the operating channel this function should also take
into account the reg domain for completeness.
>
>So to solve the issue, the right approach should be "check if DFS
>channels and check if CAC is done".

We can't scan while CAC is in progress but why must we verify that CAC was =
done
in order to perform a scan operation?
>
>You may refer how "cfg80211_reg_can_beacon()" is doing for that.
>
>
>Thanks,
>
>Peter

Thanks,
Aaron