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DateTue, 15 Jan 2002 16:16:53 +0100
FromGerd Knorr <>
SubjectRe: Memory problem with bttv driver
On Tue, Jan 15, 2002 at 02:46:52PM +0100, Stephan von Krawczynski wrote:
> On Tue, 15 Jan 2002 14:20:17 +0100
> Gerd Knorr <kraxel@bytesex.org> wrote:
> 
> > Yes.  Instead of remapping vmalloced kernel memory it gives you shared
> > anonymous pages, then does zerocopy DMA using kiobufs.  You may run in
> > trouble with >4GB machines.
> 
> Interesting.
> What's the problem on > 4GB ?

The bt878/848 is a 32bit PCI device, it simply can't go DMA to main
memory above 4GB.  At least on ia32, on architecures with a iommu
(sparc, ...) it should work without trouble.

  Gerd

-- 
#define	ENOCLUE 125 /* userland programmer induced race condition */
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