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Document BUS_DMA_NOCACHE.

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MFC after:	3 days
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Konstantin Belousov 2008-09-06 15:21:01 +00:00
parent 3c8574bc8a
commit d56aeabac3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=182816
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7
share/man/man9/bus_dma.9
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@ -547,6 +547,13 @@ Are as follows:
.It Dv BUS_DMA_NOWAIT
The load should not be deferred in case of insufficient mapping resources,
and instead should return immediately with an appropriate error.
.It Dv BUS_DMA_NOCACHE
The allocated memory will not be cached in the processor caches.
All memory accesses appear on the bus and are executed
without reordering.
Currently, the flag is implemented for i386 and amd64 architectures
only, where it results in the Strong Uncacheable
PAT to be set for the allocated virtual address range.
.El
.El
.Pp