svn commit: r250355 - head/sys/dev/ath

[Adrian Chadd]

Author: adrian
Date: Wed May  8 07:30:33 2013
New Revision: 250355
URL: http://svnweb.freebsd.org/changeset/base/250355

Log:
  Revert a previous commit - this is causing hardware errors.
  
  I'm not sure why this is failing.  The holding descriptor should be being
  re-read when starting DMA of the next frame.  Obviously something here
  isn't totally correct.
  
  I'll review the TX queue handling and see if I can figure out why this
  is failing.  I'll then re-revert this patch out and use the holding
  descriptor again.

Modified:
  head/sys/dev/ath/if_ath.c
  head/sys/dev/ath/if_ath_misc.h

Modified: head/sys/dev/ath/if_ath.c
==============================================================================
--- head/sys/dev/ath/if_ath.c	Wed May  8 07:14:07 2013	(r250354)
+++ head/sys/dev/ath/if_ath.c	Wed May  8 07:30:33 2013	(r250355)
@@ -4000,20 +4000,19 @@ ath_tx_processq(struct ath_softc *sc, st
 			break;
 		}
 		ATH_TXQ_REMOVE(txq, bf, bf_list);
-
-		/*
-		 * Always mark the last buffer in this list as busy.
-		 *
-		 * The hardware may re-read the holding descriptor
-		 * even if we hit the end of the list and try writing
-		 * a new TxDP.
-		 *
-		 * If there's no holding descriptor then this is the
-		 * last buffer in the list of buffers after a fresh
-		 * reset; it'll soon become the holding buffer.
-		 */
-		bf->bf_last->bf_flags |= ATH_BUF_BUSY;
-
+		if (txq->axq_depth > 0) {
+			/*
+			 * More frames follow.  Mark the buffer busy
+			 * so it's not re-used while the hardware may
+			 * still re-read the link field in the descriptor.
+			 *
+			 * Use the last buffer in an aggregate as that
+			 * is where the hardware may be - intermediate
+			 * descriptors won't be "busy".
+			 */
+			bf->bf_last->bf_flags |= ATH_BUF_BUSY;
+		} else
+			txq->axq_link = NULL;
 		if (bf->bf_state.bfs_aggr)
 			txq->axq_aggr_depth--;
 

Modified: head/sys/dev/ath/if_ath_misc.h
==============================================================================
--- head/sys/dev/ath/if_ath_misc.h	Wed May  8 07:14:07 2013	(r250354)
+++ head/sys/dev/ath/if_ath_misc.h	Wed May  8 07:30:33 2013	(r250355)
@@ -131,10 +131,16 @@ extern	void ath_start_task(void *arg, in
 static inline void
 ath_tx_kick(struct ath_softc *sc)
 {
+	struct ieee80211com *ic = sc->sc_ifp->if_l2com;
 
+	IEEE80211_TX_UNLOCK_ASSERT(ic);
+	ATH_TX_UNLOCK_ASSERT(sc);
+
+	IEEE80211_TX_LOCK(ic);
 	ATH_TX_LOCK(sc);
 	ath_start(sc->sc_ifp);
 	ATH_TX_UNLOCK(sc);
+	IEEE80211_TX_UNLOCK(ic);
 }
 
 /*