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Subject: Re: How many null-data probes on connection loss?
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Ben Greear <greearb@candelatech.com>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Date:   Wed, 26 Sep 2018 10:38:57 +0200
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On Tue, 2018-09-25 at 16:12 -0700, Ben Greear wrote:
> While testing out some other issue, I noticed that my ath10k system creates
> several hundred null-data probes when I abruptly down the AP the station
> is connected to.
> 
> I guess this is because I use the mac80211 stack to handle the probes, and
> the firmware then retries each mac80211 probe many times.
> 
> So, in the case where mac80211 is sending a null-data probe, is the assumption
> that the driver will try each frame exactly once?

Not really, it should be treated like any other management frame.

> Or is several hundred frames expected?  I'm guessing the former, but before I go
> hacking firmware, I thought I would ask...

Certainly not several hundred, but maybe a dozen? I think iwlwifi uses
16, and minstrel would set up max_rate_tries, which drivers set to
somewhere between 1 and 18? One seems s a bit low, mt76?

johannes