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Date: Thu, 2 Feb 2012 18:06:36 +0200
Message-ID: <CAK80WHbAE0+NhLgLAxE+6BmkHFy2hw=sNV1TBjjOTajhHcdxRw@mail.gmail.com> (sfid-20120202_170640_938821_B76BE1B7)
Subject: Re: [RFC 3/9] nl80211/cfg80211: add ability to enable TX on op-channel
From: "Goldenshtein, Victor" <victorg@ti.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org, kgiori@qca.qualcomm.com,
	mcgrof@frijolero.org, zefir.kurtisi@neratec.com,
	adrian.chadd@gmail.com, j@w1.fi, coelho@ti.com, assaf@ti.com,
	yoni.divinsky@ti.com, igalc@ti.com, adrian@freebsd.org,
	nbd@nbd.name
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Sender: linux-wireless-owner@vger.kernel.org

On Tue, Jan 31, 2012 at 7:43 AM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On 1/26/2012 4:37 AM, Victor Goldenshtein wrote:
>>
>> The dfs master device should monitor radar channels
>> for potential radar interference for a minimum of
>> CAC (channel availability check) time, during this
>> period no tx can occur. If no radar interference
>> is detected the dfs master may initiate the tx with
>> new NL80211_CMD_DFS_ENABLE_TX command.
>
>
> So do we think that no safeguards here at all are acceptable? Not even
> checking that radar detection was enabled, CAC time expired, etc.?

We can add a check whether dfs is supported by the driver
(rdev->wiphy.features & NL80211_FEATURE_DFS).

The nl/cfg/mac doesn't have the info whether the radar detection is
enabled and definitely doesn't heard about CAC time, on other hand the
driver which starts/handles radar detection know whether it started or
not. I think the driver should perform this simple "sanity" checks,
otherwise we"ll need to save different DFS states in the mac, not sure
that this is what we want.


-- 
Thanks,
Victor.