Author: sbruno
Date: Fri Mar 2 16:38:54 2012
New Revision: 232397
URL: http://svn.freebsd.org/changeset/base/232397
Log:
MFC r232267 via stable/8 MFC r232354
Workaround for PCIe 4GB boundary issue
Enforce a boundary of no more than 4GB - transfers crossing a 4GB
boundary can lead to data corruption due to PCIe limitations. This
change is a less-intrusive workaround that can be quickly merged back
to older branches; a cleaner implementation will arrive in HEAD later
but may require KPI changes.
This change is based on a suggestion by jhb@.
Modified:
stable/7/sys/amd64/amd64/busdma_machdep.c
stable/7/sys/i386/i386/busdma_machdep.c
Directory Properties:
stable/7/sys/ (props changed)
Modified: stable/7/sys/amd64/amd64/busdma_machdep.c
==============================================================================
--- stable/7/sys/amd64/amd64/busdma_machdep.c Fri Mar 2 16:35:18 2012
(r232396)
+++ stable/7/sys/amd64/amd64/busdma_machdep.c Fri Mar 2 16:38:54 2012
(r232397)
@@ -215,6 +215,10 @@ bus_dma_tag_create(bus_dma_tag_t parent,
bus_dma_tag_t newtag;
int error = 0;
+ /* Always enforce at least a 4GB boundary. */
+ if (boundary == 0 || boundary > ((bus_addr_t)1 << 32))
+ boundary = (bus_size_t)1 << 32;
+
/* Basic sanity checking */
if (boundary != 0 && boundary < maxsegsz)
maxsegsz = boundary;
Modified: stable/7/sys/i386/i386/busdma_machdep.c
==============================================================================
--- stable/7/sys/i386/i386/busdma_machdep.c Fri Mar 2 16:35:18 2012
(r232396)
+++ stable/7/sys/i386/i386/busdma_machdep.c Fri Mar 2 16:38:54 2012
(r232397)
@@ -220,6 +220,12 @@ bus_dma_tag_create(bus_dma_tag_t parent,
bus_dma_tag_t newtag;
int error = 0;
+#if defined(PAE)
+ /* Need at least a 4GB boundary, PAE limitations require 2GB */
+ if (boundary == 0 || boundary > ((bus_addr_t)1 << 31))
+ boundary = (bus_size_t)1 << 31;
+#endif
+
/* Basic sanity checking */
if (boundary != 0 && boundary < maxsegsz)
maxsegsz = boundary;
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
