Messages in this thread |  | | Date | Tue, 15 Jan 2002 17:35:51 +0100 | From | Stephan von Krawczynski <> | Subject | Re: Memory problem with bttv driver |
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On Tue, 15 Jan 2002 16:16:53 +0100 Gerd Knorr <kraxel@bytesex.org> wrote:
> 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.
Sorry, maybe I should have clarified: what is the problem with allocating those pages below 4GB in a >4GB box?
Regards, Stephan
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