svn commit: r216970 - head/sys/dev/bge

[Pyun YongHyeon]

Author: yongari
Date: Tue Jan  4 19:10:54 2011
New Revision: 216970
URL: http://svn.freebsd.org/changeset/base/216970

Log:
  Partially revert change made in r212061. r212061 relied on
  bus_dma(9)'s capability which honors boundary restrictions of DMA
  tag for dynamic buffers. However it seems this does not work well
  and it triggered watchodg timeouts on controller that has the
  hardware bug. It's not clear whether there is still another
  hardware bug not mentioned in errata. This should be revisited
  since this change shall make use of bounce buffers which in turn
  reduces performance a lot on systems that have more than 4GB
  memory.
  
  Reported by:	Michael L. Squires (mikes <> siralan dot org)
  Tested by:	Michael L. Squires (mikes <> siralan dot org)
  MFC after:	3 days

Modified:
  head/sys/dev/bge/if_bge.c

Modified: head/sys/dev/bge/if_bge.c
==============================================================================
--- head/sys/dev/bge/if_bge.c	Tue Jan  4 19:09:05 2011	(r216969)
+++ head/sys/dev/bge/if_bge.c	Tue Jan  4 19:10:54 2011	(r216970)
@@ -2475,8 +2475,15 @@ bge_dma_alloc(struct bge_softc *sc)
 	boundary = 0;
 	if ((sc->bge_flags & BGE_FLAG_4G_BNDRY_BUG) != 0)
 		boundary = BGE_DMA_BNDRY;
+	/*
+	 * XXX
+	 * It seems bus_dma(9) still has issue on dealing with boundary
+	 * restriction for dynamic buffers so disable the boundary
+	 * restriction and limit DMA address space to 32bit.  It's not
+	 * clear whether there is another hardware issue here.
+	 */
 	error = bus_dma_tag_create(bus_get_dma_tag(sc->bge_dev),
-	    1, boundary, lowaddr, BUS_SPACE_MAXADDR, NULL,
+	    1, 0, BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL,
 	    NULL, BUS_SPACE_MAXSIZE_32BIT, 0, BUS_SPACE_MAXSIZE_32BIT,
 	    0, NULL, NULL, &sc->bge_cdata.bge_buffer_tag);
 	if (error != 0) {