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From: Stanislaw Gruszka <sgruszka@redhat.com>
To: linux-wireless@vger.kernel.org
Cc: "Tomislav Požega" <pozega.tomislav@gmail.com>,
	"Daniel Golle" <daniel@makrotopia.org>,
	"Felix Fietkau" <nbd@nbd.name>, "Mathias Kresin" <dev@kresin.me>
Subject: Re: [RFC/RFT v2] rt2x00: do not set IEEE80211_TX_STAT_AMPDU_NO_BACK on tx status
Date: Fri, 23 Aug 2019 08:51:41 +0200	[thread overview]
Message-ID: <20190823065141.GA10462@redhat.com> (raw)
In-Reply-To: <20190712103228.17658-1-sgruszka@redhat.com>

On Fri, Jul 12, 2019 at 12:32:28PM +0200, Stanislaw Gruszka wrote:
> According to documentation IEEE80211_TX_STAT_AMPDU_NO_BACK is suppose
> to be used when we do not receive BA (BlockAck). However on rt2x00 we
> use it when remote station fail to decode one or more subframes within
> AMPDU (some bits are not set in BlockAck bitmap). Setting the flag result
> in sent of BAR (BlockAck Request) frame and this might result of abuse
> of BA session, since remote station can sent BA with incorrect
> sequence numbers after receiving BAR. This problem is visible especially
> when connecting two rt2800 devices.
> 
> Previously I observed some performance benefits when using the flag
> when connecting with iwlwifi devices. But currently possibly due
> to recent changes in rt2x00 removing the flag has no effect on
> those test cases.
> 
> So remove the IEEE80211_TX_STAT_AMPDU_NO_BACK.
> 
> Additionally partially mimic mt76 behaviour: send BAR when
> starting/stopping BA session to workaround problems with some buggy
> clients. Do not sent BAR on PS wakeup since we lack all PS handling
> code what mt76 has.

Currently Felix posted patch that removed sending BAR on BA session
stop. And I do not see necessity for sending BAR on start, so I will
precede with first version of this patch, that just remove NO_BACK
flag. 

Stanislaw

      reply	other threads:[~2019-08-23  6:51 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-12 10:32 [RFC/RFT v2] rt2x00: do not set IEEE80211_TX_STAT_AMPDU_NO_BACK on tx status Stanislaw Gruszka
2019-08-23  6:51 ` Stanislaw Gruszka [this message]

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