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    SubjectRe: [PATCH] Prevent reserving RAM in the region already reserved by BIOS
    From
    it' s not in ISA space.
    once loading the NVIDIA driver, the warnign oops shows up.
    4K starting at 0x9f800 (i.e. to 0xa007ff) overlap with the ISA space
    (starting at 0xa0000).

    When I don' t load the driver, no oops.
    So I am assuming nvidia driver request 4K of memory, that happens to
    be available in the bios area.

    I think that there is a check missing somewhere to report that
    available RAM buffer is already reserved (by BIOS) so we need to get
    it from somewhere else.

    Does it make sense?
    -Mathieu

    On Wed, May 19, 2010 at 4:00 PM, H. Peter Anvin <hpa@zytor.com> wrote:
    > On 05/19/2010 03:58 PM, Mathieu Rondonneau wrote:
    >> Thanks for the feedback.
    >>
    >> No, I don' t see any changes in the /proc/iomem.
    >>
    >> I am trying to prevent a ioremap of a 4K size on a non aligned 4K
    >> address that is below the ISA_START_ADDRESS.
    >>
    >> The problem generates a oops about overlapping.
    >> I have a fix which instruct to not to do any re-map if the section
    >> name is "reserved".
    >> Which is not really clean.
    >> I am looking for a clean way to tell the ioremap function to not remap
    >> bios reserved memory.
    >> That' s why I thought the e820 would be a good start.
    >>
    >> I will continue looking into this. It does not crash the systems. A
    >> warning generates the oops.
    >>
    >
    > Why are you mapping a fixed-address in ISA space to begin with?
    >
    > Requests to a fixed address (as opposed to dynamic allocation) have to
    > be granted even in reserved space -- after all, that's what the address
    > might be reserved for!
    >
    >        -hpa
    >
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