svn commit: r232753 - head/sys/dev/ath

[Adrian Chadd]

Author: adrian
Date: Fri Mar  9 22:58:34 2012
New Revision: 232753
URL: http://svn.freebsd.org/changeset/base/232753

Log:
  Document that we may end up with some suboptimal handling of data
  frames with stations in power saving mode.
  
  I'm not (yet) sure how to handle TX'ing aggregates frames to stations
  that are in power saving mode, or whether that's even a feasible thing
  to do. So in order to (mostly) not forget, leave a couple of comments
  in the code.
  
  The code presently assumes that the aggregation TID state for an ath_node
  is locked not by the ath_node lock or a node+TID lock, but behind the
  hardware queue said TID maps to.  This assumption is going to be
  incorrect for stations in power saving mode as we'll be TX'ing frames
  on the multicast queue.
  
  In any case, I'm afraid its a "later problem". :/

Modified:
  head/sys/dev/ath/if_ath_tx.c

Modified: head/sys/dev/ath/if_ath_tx.c
==============================================================================
--- head/sys/dev/ath/if_ath_tx.c	Fri Mar  9 22:41:09 2012	(r232752)
+++ head/sys/dev/ath/if_ath_tx.c	Fri Mar  9 22:58:34 2012	(r232753)
@@ -1162,6 +1162,11 @@ ath_tx_normal_setup(struct ath_softc *sc
 	 * (or) if there is some mcast data waiting on the mcast
 	 * queue (to prevent out of order delivery) multicast
 	 * frames must be buffered until after the beacon.
+	 *
+	 * XXX This likely means that if there's a station in power
+	 * save mode, we won't be doing any kind of aggregation towards
+	 * anyone.  This is likely a very suboptimal way of dealing
+	 * with things.
 	 */
 	if (ismcast && (vap->iv_ps_sta || avp->av_mcastq.axq_depth))
 		txq = &avp->av_mcastq;
@@ -1409,6 +1414,12 @@ ath_tx_start(struct ath_softc *sc, struc
 	if (ismcast)
 		txq = &avp->av_mcastq;
 
+	/*
+	 * XXX This likely means that if there's a station in power
+	 * save mode, we won't be doing any kind of aggregation towards
+	 * anyone.  This is likely a very suboptimal way of dealing
+	 * with things.
+	 */
 	if ((! is_ampdu) && (vap->iv_ps_sta || avp->av_mcastq.axq_depth))
 		txq = &avp->av_mcastq;