Hello Christian, thanks for your explanation! Christian Lamparter wrote: > On Monday, December 03, 2012 03:13:55 PM Andreas Hartmann wrote: >> Stanislaw Gruszka wrote: >>> Commit f0425beda4d404a6e751439b562100b902ba9c98 "mac80211: retry sending >>> failed BAR frames later instead of tearing down aggr" caused regression >>> on rt2x00 hardware (connection hangs). >> >> This patch caused a problem, too, with carl9170 >> (http://thread.gmane.org/gmane.linux.kernel.wireless.general/92203/focus=92376). >> How did they fix it (the thread unfortunately ends without any solution >> / patch). > > This was fixed by: carl9170: fix HT peer BA session corruption > (c9122c0d63a50 in wireless-testing). The issue here is that the > hardware does not set the tx success bit when it receives a > BA for a sent BAR [looks like it is expecting a legacy ACK?! > but who knows - the original vendor driver [otus] didn't really > deal with BARs anyway]. If I got Helmut correctly here (http://news.gmane.org/find-root.php?group=gmane.linux.kernel.wireless.general&article=83762), rt2x00pci could have a related problem (probably missing tx status). Wouldn't it be an idea to try a similar approach? https://kernel.googlesource.com/pub/scm/linux/kernel/git/linville/wireless-testing/+/c9122c0d63a50bab0a97dc936a38c0f921b6930e^!/ > So the driver has to do that job and currently it's done in > the following way: > When mac80211 sends a BAR, the driver will keep a reference of > the frame around in ar->bar_list, before it is sent on its way. > If the device receives a BA within the retry window then the > driver's rx-path will enter carl9170_ba_check. This function > sets the TX_STAT_ACK flag [for the BAR] if the incoming BA > matches. > > While there are a few problems with this approach [added tx and rx > overhead due to flexible ba filtering and bar queuing, unwanted BAR > retries, ...], it was one of the better solution which was within > the capabilities of the hardware, firmware and driver. > Obviously, if the ar9170 hardware would just set that tx success > bit [ath9k mac does this properly], this wouldn't be necessary. > > Regards, > Chr Thanks, kind regards, Andreas -- 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
