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Subject: Re: Flag for detecting 802.11r Fast BSS Transition support
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <CA+ASDXOyXb0dPGOrjQR7C-b6dyftiZhkta3cwG28B9sC5wxHxQ@mail.gmail.com>
Date:   Fri, 16 Aug 2019 20:54:46 +0200
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        Matthew Wang <matthewmwang@google.com>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        Kirtika Ruchandani <kirtika@google.com>, j@w1.fi
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 <211816ff03cf188d834a21b1fbc98b4f8c5b81f4.camel@sipsolutions.net>
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To:     Brian Norris <briannorris@chromium.org>
Sender: linux-wireless-owner@vger.kernel.org
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Hi Brian,

>> So I guess you'd have to figure out what operations the drivers need to
>> support then? I'm not even sure how wpa_s would handle this for SME
>> offload devices.
> 
> I'm not intimately familiar with FT, but it looks like the only thing
> wpa_supplicant is asking for is NL80211_CMD_UPDATE_FT_IES. I see
> exactly one driver that implements this, but there's no flag for it.
> Well, I guess we could just run the command and look for EOPNOTSUPP...

this kind of API design and usage is bad. Try-and-error approach is just not sustainable. Even while it is late to add a proper flag that indicates support, we need to do this to make nl80211 better for the future.

Regards

Marcel