On Friday 15 August 2008, Mikko Virkkilä wrote: > I'm moving the conversation over from rt2400-devel to linux-wireless. > The last message (as of this writing) from the earlier conversation at > rt2400-devel can be found at http://tinyurl.com/6p9n7g with some more > details. > > So to summarize the situation: > > - the rt73usb driver (in rt2x00) doesn't set IEEE80211_TX_STAT_ACK > because "frames which are uploaded to the hardware are not guarenteed > to be acked". rt2500usb suffers from the same issue. > - The mac80211 layer will set the IEEE80211_RADIOTAP_F_TX_FAIL if the > IEEE80211_TX_STAT_ACK flag is missing. > - hostapd will interpret the IEEE80211_RADIOTAP_F_TX_FAIL as a failure > to send > > This all results in hostapd reporting "MGMT (TX callback) fail" and > making rt73usb not work in AP mode. > > I'm hoping that some decision can be reached on how to fix this so that > AP mode will work with the rt73. > > Just off the top of my head, one way of fixing this would be to make > IEEE80211_TX_CTL_NO_ACK also work the other way around: Now it is used > to tell the lower level not to wait for an ACK. Perhaps it could also be > used by the lower level to tell higher levels that no ACK is ever going > to come e.g. because the hardware is incapable of supplying TX ACKs. The > mac80211 layer would be changed to check for IEEE80211_TX_CTL_NO_ACK. If > the flag was set it would skip setting IEEE80211_RADIOTAP_F_TX_FAIL even > when the IEEE80211_TX_STAT_ACK is missing. Actually this isn't the complete picture, what you might need is a new flag IEEE80211_TX_CTL_UNKNOWN which then informs mac80211 that the frame has an unknown status, and that is something that could be passed on to userspace through radiotap later. This is better then setting a global "supports ACK reporting" flag, because in case of rt61 one every x frames also has an unknown status because the txdone interrupt isn't happening for that frame. So that means you definately need a per-frame flag to tell if the frame was acked, not-acked or if the status was unknown. Ivo -- 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
