Hi, [CC'ing Jay and Eddy as they might be able to answer some questions regarding 11n aggregation on rt2800 devices] I'm using rt2800pci as AP. 11n aggregation works just fine when using a Intel 5100 client and transferring data in both directions on Linux. Also my Intel 4965 works just fine. However, using Windows Vita on the same machine (Intel 5100) the Intel RX reorder buffer seems to get confused. At least I can see (I can also provide a pcap if anyone is interested) that the Intel STA still BlockAcks received AMPDUs but the frames never make it out of the driver. It seems as if they are stuck in the Intel driver/firmware (Windows). I first thought this might be due to an old windows driver but even after updating it to the newest version I can still reproduce this issue. After debugging some more I noticed that this issue seems to appear as soon as some parts (or maybe all parts) of an AMPDU (rt2800pci -> Intel 5100 Windows STA) are not BlockAcked and need to be retried. However, as far as I can see the whole aggregation stuff including retransmissions on failures should be handled entirely in hardware (only the BA session setup/teardown is done by the driver/mac80211). According to 802.11n-2009 the BA originator could send a BlockAckReq if an AMPDU is not BlockAcked in time. However, I never see the hw sending a BlockAckReq. Jay, Eddy, does the hw ever send a BlockAckReq if it doesn't receive a BlockAck for an AMPDU? At least, I hacked rt2x00 to set IEEE80211_TX_STAT_AMPDU_NO_BACK for failed aggregated frames such that mac80211 sends a BlockAckReq for this failed MPDU and this indeed seems to improve the situation but doesn't fix it completely. Anything else I could try? Any ideas? Thanks, Helmut -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
