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    SubjectRe: [PATCH 6/13] devres: implement managed iomap interface
    Tejun Heo wrote:

    >> A very late comment but nevertheless... :-)

    > Better late than never.


    >> Those functions are going to break on 32-bit platforms with
    >> extended physical address (well, that's starting with Pentiums which
    >> had 36-bit PAE :-) AND devices mapped beyond 4 GB (e.g. PowerPC 44x).
    >> You should have used resource_size_t for the 'offset' parameter. As
    >> this most probably means that libata is broken on such platforms, I'm
    >> going to submit a patch...

    It's broken with drivers using MMIO, I meant to say.

    > Yeah, right please go ahead. But I wonder whether any BIOS was actually
    > crazy enough to map mmio region above 4G on 32bit machine.

    This is a *hardware* mapping on some non-x86 platforms (like PPC 44x or
    MIPS Alchemy). The arch/ppc/ and arch/mips/ kernels have special hooks called
    from ioremap() which help create an illusion that the PCI memory space on such
    platforms (not only it) is mapped below 4 GB; arch/powerpc/ kernel doesn't do
    this anymore -- hence this newly encountered issue.

    WBR, Sergei

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