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To:     Kalle Valo <kvalo@codeaurora.org>
Cc:     linux-wireless@vger.kernel.org, hurricos@gmail.com
References: <20210214184911.96702-1-nbd@nbd.name>
 <8735xyrkvy.fsf@codeaurora.org>
From:   Felix Fietkau <nbd@nbd.name>
Subject: Re: [PATCH] ath9k: fix transmitting to stations in dynamic SMPS mode
Message-ID: <d668f30a-f911-921f-d329-f6ac872d0bcc@nbd.name>
Date:   Mon, 15 Feb 2021 08:20:04 +0100
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On 2021-02-15 05:54, Kalle Valo wrote:
> Felix Fietkau <nbd@nbd.name> writes:
> 
>> When transmitting to a receiver in dynamic SMPS mode, all transmissions that
>> use multiple spatial streams need to be sent using CTS-to-self or RTS/CTS to
>> give the receiver's extra chains some time to wake up.
>> This fixes the tx rate getting stuck at <= MCS7 for some clients, especially
>> Intel ones, which make aggressive use of SMPS.
>>
>> Cc: stable@vger.kernel.org
>> Reported-by: Martin Kennedy <hurricos@gmail.com>
>> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> 
> No Fixes tag so I assume this is not a regression?
> 
> Should this go to v5.12 or -next? I guess that depends how much testing
> this patch has got.
I'd prefer v5.12. I got confirmation that the patch makes a big
difference in throughput with Intel clients (makes tx with MCS > 7
work), and I think there is very little potential for regressions.

- Felix