On Thu, Jul 04, 2019 at 01:06:52PM +0200, Stanislaw Gruszka wrote: > According to documentation IEEE80211_TX_STAT_AMPDU_NO_BACK is suppose > to be used when we do not recive 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 reacent changes in rt2x00 removing the flag has no effect on > those test cases. > > So remove the IEEE80211_TX_STAT_AMPDU_NO_BACK. > > Perhaps we should send BAR exlicitly on BA session start/stop > and when remote STA went to PowerSave mode (for AP) like mt76 does. > But I do not understand for what this is needed.
This commit https://github.com/openwrt/mt76/commit/3e447e7797d64dbf4dc1dd5553d08be0d8150d7e explained that sending BAR on stop aggregation is workaround for buggy clients. I can implement that on rt2x00. But I will skip sending BAR on remote station PS wakeup, since we do not implement all PS related code in rt2x00. Stanislaw
