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    SubjectRe: mm question
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    > "AGP addressable" memory which is ~64meg less than the total amount on my
    > machine. However, looking around in AGP driver or AGP specs does not seem
    > to indicate any restriction of the sort and, moreover, I do not need AGP
    > for this DMA transfer (it is PCI only).

    Can the transfer go to pages mapped into the AGP gart, using their gart
    side mapping ?

    > Better than giving up.. Unfortunately looking around in
    > linux/Documentation and drivers did not yield much in terms of
    > explanation. I know I can use mem_map_reserve to reserve a page but I
    > don't know how to get page struct from a physical address nor which lock
    > to use when messing with this.

    You have to grab them at boot time via bootmem to get them in a range of
    your choice. Otherwise you can use

    get_free_page - grab a page
    virt_to_page - page struct of page
    virt_to_bus - bus addr of page

    virt_to_bus isnt portable because real world pci bus mapping on non x86 is
    deeply murky and mysterious. But you probably want to worry about that
    after it works.

    Alan
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