svn commit: r196381 - in stable/8/sys: . amd64/include/xen cddl/contrib/opensolaris contrib/dev/acpica contrib/pf dev/usb dev/xen/xenpci

Rafal Jaworowski raj at
Wed Aug 19 14:48:59 UTC 2009

Author: raj
Date: Wed Aug 19 14:48:59 2009
New Revision: 196381

  MFC r196380
  Fix USB cache sync operations for platforms with non-coherent DMA.
  - usb_pc_cpu_invalidate() is called between [consecutive] reads from a device,
    so a sequence of BUS_DMASYNC_POSTREAD and _PREREAD should be used. Note we
    cannot use or'ed shorthand ( _POSTREAD | _PREREAD) for BUS_DMASYNC flags, as
    the low level bus dma sync operation is implementation dependent and we
    cannot assume the required order of operations to be guaranteed.
  - usb_pc_cpu_flush() is called before writing to a device, so
    BUS_DMASYNC_PREWRITE should be used.
  Submitted by:	Grzegorz Bernacki
  Reviewed by:	HPS, arm@, usb@ ML
  Tested by:	HPS, Mike Tancsa
  Approved by:	re (kib)
  Obtained from:	Semihalf

  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/usb/usb_busdma.c
--- stable/8/sys/dev/usb/usb_busdma.c	Wed Aug 19 14:39:08 2009	(r196380)
+++ stable/8/sys/dev/usb/usb_busdma.c	Wed Aug 19 14:48:59 2009	(r196381)
@@ -679,8 +679,8 @@ usb_pc_cpu_invalidate(struct usb_page_ca
 		/* nothing has been loaded into this page cache! */
-	bus_dmamap_sync(pc->tag, pc->map,
+	bus_dmamap_sync(pc->tag, pc->map, BUS_DMASYNC_POSTREAD);
+	bus_dmamap_sync(pc->tag, pc->map, BUS_DMASYNC_PREREAD);
@@ -693,8 +693,7 @@ usb_pc_cpu_flush(struct usb_page_cache *
 		/* nothing has been loaded into this page cache! */
-	bus_dmamap_sync(pc->tag, pc->map,
+	bus_dmamap_sync(pc->tag, pc->map, BUS_DMASYNC_PREWRITE);

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