Jouni Malinen <j@xxxxx> writes: > On Sun, Mar 15, 2009 at 10:07:39PM +0200, Kalle Valo wrote: >> ieee80211_tx_h_check_assoc() was dropping everything else than probe >> requests during software scan. So the null frame with the power save >> bit was dropped and AP never received it. This meant that AP never >> buffered any frames for the station during software scan. >> >> Fix this by allowing to transmit both probe request and null frames >> during software scan. Tested with stlc45xx. > > I would assume the nullfunc frames are sent only just before the scan > and just after the scan, not really "during" the scan. Or am I missing > something here? No, you are not missing anything. I just considered the start of scan happening in the beginning of function ieee80211_start_scan() (which sends the nullfunc frame) and that's why I chose the word "during". >> --- a/net/mac80211/tx.c >> +++ b/net/mac80211/tx.c >> @@ -193,7 +193,14 @@ ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx) >> return TX_CONTINUE; >> >> if (unlikely(tx->local->sw_scanning) && >> - !ieee80211_is_probe_req(hdr->frame_control)) >> + !ieee80211_is_probe_req(hdr->frame_control) && >> + !ieee80211_is_nullfunc(hdr->frame_control)) >> + /* >> + * When software scanning only null frames (to notify the >> + * sleep state to the AP) and probe requests (for the >> + * active scan) are allowed, everything else should be >> + * dropped. >> + */ >> return TX_DROP; > > While this is probably the easiest way of fixing the issue you are > seeing, the more correct operation would be to allow nullfunc frames > only at the beginning and end of the scan operation, not during it, > i.e., there is no point allowing those frames to go out when we are not > on our operational channel. I would hope we do not currently send those > frames at such time, Actually I was thinking of adding a WARN_ONCE just to catch that but I decided to abandon the idea because all the blame I would get from the warnings :) > so this should not matter much, but the comment could be made more > clear about the different needs for nullfunc frames (please also > s/null frames/nullfunc frames/) and probe request frames. The former > are sent only on the operational channel in the beginning and end of > scan while the latter are sent on the channels to be scanned during > an active scan. Should the description be in ieee80211_start_scan() in scan.c? I think it would make more sense to have it there instead of tx.c. I can then add a reference to the comment above. -- Kalle Valo -- 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
