Subject: Re: [RFC PATCH v3 08/12] iwlwifi: dvm - EXT_KEY_ID A-MPDU API update
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org
References: <20190210210620.31181-1-alexander@wetzel-home.de>
 <20190210210620.31181-9-alexander@wetzel-home.de>
 <63fecadcf3f38f24b547143d9d53b3454adc417a.camel@sipsolutions.net>
From:   Alexander Wetzel <alexander@wetzel-home.de>
Message-ID: <4bd73bd3-9027-4689-54e7-7c082eefa327@wetzel-home.de>
Date:   Fri, 22 Feb 2019 22:15:08 +0100
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> On Sun, 2019-02-10 at 22:06 +0100, Alexander Wetzel wrote:
>> When using Extended Key ID mac80211 drops @IEEE80211_TX_CTL_AMPDU for
>> the last packet which can be added to a A-MPDU in preparation.
>>
>> Don't throw a warning and just handle the frame as if
>> @IEEE80211_TX_CTL_AMPDU would have been set.
>>
>> Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
>> ---
>>
>> I cold not figure out so far how to make sure the card will not mix
>> A-MPDU frames. Looks like that is handled fully in the HW and I didn't
>> find any interface to influence it. (It even may work already, I have
>> some problems to capture A-MPDU frames with A-MPDU information intact
>> and the topic was pretty low on the list so far. After all it works...)
> 
> You can't really do that, as far as I can tell, unfortunately. So this
> might be better in a "compat on steroids" mode?

I hoped that the HW would already enforce the key border. But ok: The 
cards will still be able to use NATIVE mode. Only now the driver will 
have to request to disable Tx aggregation when finding a key border. 
Since Tx aggregation is disabled per default anyhow many users will not 
even see a difference.

(Off topic here, but I suspect the not reproducible problems leading to 
change the Tx aggregation default to off could also have been ptk0 rekey 
freezes. In that case we could now allow it again. But I've not found 
raw error reports and guess it's not worth the efforts/risks to change 
the default again.)

Alexander