svn commit: r206575 - stable/8/sys/dev/msk

[Pyun YongHyeon]

Author: yongari
Date: Wed Apr 14 00:50:18 2010
New Revision: 206575
URL: http://svn.freebsd.org/changeset/base/206575

Log:
  MFC r206364:
    Partial revert r204545.
    Just relying on status LE ownership of status block seems to cause
    poor performance. Always read current status index register first
    and then check status ownership as we had before. Accessing status
    index register seems to trigger immediate status update if
    controller have pending status updates.
  
    Reported by:	Andre Albsmeier <Andre.Albsmeier <> siemens dot com>
    Tested by:	Andre Albsmeier <Andre.Albsmeier <> siemens dot com>

Modified:
  stable/8/sys/dev/msk/if_msk.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)

Modified: stable/8/sys/dev/msk/if_msk.c
==============================================================================
--- stable/8/sys/dev/msk/if_msk.c	Wed Apr 14 00:50:09 2010	(r206574)
+++ stable/8/sys/dev/msk/if_msk.c	Wed Apr 14 00:50:18 2010	(r206575)
@@ -3327,6 +3327,9 @@ msk_handle_events(struct msk_softc *sc)
 	uint32_t control, status;
 	int cons, len, port, rxprog;
 
+	if (sc->msk_stat_cons == CSR_READ_2(sc, STAT_PUT_IDX))
+		return (0);
+
 	/* Sync status LEs. */
 	bus_dmamap_sync(sc->msk_stat_tag, sc->msk_stat_map,
 	    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
@@ -3407,7 +3410,7 @@ msk_handle_events(struct msk_softc *sc)
 	if (rxput[MSK_PORT_B] > 0)
 		msk_rxput(sc->msk_if[MSK_PORT_B]);
 
-	return (rxprog > sc->msk_process_limit ? EAGAIN : 0);
+	return (sc->msk_stat_cons != CSR_READ_2(sc, STAT_PUT_IDX));
 }
 
 static void