From ab5b5342fd0ba5b9a2f58a94c5d41dd074b7c48e Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 7 Aug 2009 16:28:09 +0200 Subject: [PATCH] mac80211: document TX powersave filter requirements This documents what's required to implement that TX powersave filter properly wrt. handling hardware queues. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- include/net/mac80211.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 467eed71be22..cd4eb20f98f5 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -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. -- 2.20.1