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    SubjectRe: Memory problem with bttv driver
    > > > > 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

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