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| author | emaste <emaste@FreeBSD.org> | 2012-02-28 19:42:40 +0000 |
|---|---|---|
| committer | emaste <emaste@FreeBSD.org> | 2012-02-28 19:42:40 +0000 |
| commit | 40bea12fa6c45b4cd4dd90cf66c725a362f8e270 (patch) | |
| tree | 0aa2edfc17575c71bc44dc9625528ddf266b89a5 /sys/x86 | |
| parent | bfd7a07500d59035447033f67bf7408d4150ce05 (diff) | |
| download | FreeBSD-src-40bea12fa6c45b4cd4dd90cf66c725a362f8e270.zip FreeBSD-src-40bea12fa6c45b4cd4dd90cf66c725a362f8e270.tar.gz | |
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@.
Reviewed by: scottl, jhb
Sponsored by: Sandvine Incorporated
MFC after: 3 days
Diffstat (limited to 'sys/x86')
| -rw-r--r-- | sys/x86/x86/busdma_machdep.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/sys/x86/x86/busdma_machdep.c b/sys/x86/x86/busdma_machdep.c index 70dd72b..89e0e98 100644 --- a/sys/x86/x86/busdma_machdep.c +++ b/sys/x86/x86/busdma_machdep.c @@ -227,6 +227,14 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment, bus_dma_tag_t newtag; int error = 0; + /* Always enforce at least a 4GB (2GB for PAE) boundary. */ +#if defined(__amd64__) + if (boundary == 0 || boundary > ((bus_addr_t)1 << 32)) + boundary = (bus_size_t)1 << 32; +#elif defined(PAE) + 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; |
