Messages in this thread | | | Date | Wed, 16 Jan 2002 10:57:47 +0100 | From | Gerd Knorr <> | Subject | Re: Memory problem with bttv driver |
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> > > > 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?
do_anonymous_page() may give you pages above 4GB. Need to write my own nopage handler to fix this.
Gerd
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