svn commit: r212061 - head/sys/dev/bge

John Baldwin jhb at freebsd.org
Tue Aug 31 19:40:24 UTC 2010


On Tuesday, August 31, 2010 1:54:49 pm Matthew Jacob wrote:
>   But not amd64 please.
> 
> > Keep in mind the PAE case where you cannot effectively specify a 4GB
> > boundary.  I used a 2GB boundary for twa(4) in the PAE case to deal
> > with the boundary issue.  Probably though, bus_dma should just always
> > enforce a 4GB boundary, at least on x86.

Yes, thinking about this more, only i386 + PAE is special.  All other cases 
could represent the 4GB boundary restriction in a bus dma tag for the PCI bus 
(or in the platform-specific Host-PCI bridge drivers).  For i386 + PAE it 
might make sense to always enforce a 4GB boundary in the bus_dma code itself.

-- 
John Baldwin


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