From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from xc.sipsolutions.net ([83.246.72.84]:56341 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932098AbZHGO2N (ORCPT ); Fri, 7 Aug 2009 10:28:13 -0400 Subject: [PATCH] mac80211: document TX powersave filter requirements From: Johannes Berg To: John Linville Cc: linux-wireless Content-Type: text/plain Date: Fri, 07 Aug 2009 16:28:09 +0200 Message-Id: <1249655289.7194.5.camel@johannes.local> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: This documents what's required to implement that TX powersave filter properly wrt. handling hardware queues. Signed-off-by: Johannes Berg --- include/net/mac80211.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- wireless-testing.orig/include/net/mac80211.h 2009-08-07 16:24:58.000000000 +0200 +++ wireless-testing/include/net/mac80211.h 2009-08-07 16:26:46.000000000 +0200 @@ -239,7 +239,14 @@ struct ieee80211_bss_conf { * @IEEE80211_TX_CTL_AMPDU: this frame should be sent as part of an A-MPDU * @IEEE80211_TX_CTL_INJECTED: Frame was injected, internal to mac80211. * @IEEE80211_TX_STAT_TX_FILTERED: The frame was not transmitted - * because the destination STA was in powersave mode. + * because the destination STA was in powersave mode. Note that to + * avoid race conditions, the filter must be set by the hardware or + * firmware upon receiving a frame that indicates that the station + * went to sleep (must be done on device to filter frames already on + * the queue) and may only be unset after mac80211 gives the OK for + * that by setting the IEEE80211_TX_CTL_CLEAR_PS_FILT (see above), + * since only then is it guaranteed that no more frames are in the + * hardware queue. * @IEEE80211_TX_STAT_ACK: Frame was acknowledged * @IEEE80211_TX_STAT_AMPDU: The frame was aggregated, so status * is for the whole aggregation.