Date: Fri, 2 Mar 2012 16:38:55 +0000 (UTC) From: Sean Bruno <sbruno@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r232397 - in stable/7/sys: amd64/amd64 i386/i386 Message-ID: <201203021638.q22GctMk038514@svn.freebsd.org>
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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;
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