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
