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    SubjectRe: ioremap_nocache problem?

    On Tue, 23 Jan 2001, Mark Mokryn wrote:

    > ioremap_nocache does the following:
    > return __ioremap(offset, size, _PAGE_PCD);
    > However, in drivers/char/mem.c (2.4.0), we see the following:
    > /* On PPro and successors, PCD alone doesn't always mean
    > uncached because of interactions with the MTRRs. PCD | PWT
    > means definitely uncached. */
    > if (boot_cpu_data.x86 > 3)
    > prot |= _PAGE_PCD | _PAGE_PWT;
    > Does this mean ioremap_nocache() may not do the job?

    ioremap creates a new mapping that shouldn't interfere with MTRR, whereas
    you can map a MTRR mapped area into userspace. But I'm not sure if it's
    correct that no flag is set for boot_cpu_data.x86 <= 3...

    bye, Roman

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