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From: H. Peter Anvin on 19 May 2010 19:10
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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From: H. Peter Anvin on 19 May 2010 20:20
On 05/19/2010 05:01 PM, Mathieu Rondonneau wrote:
> 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

No.

The top page (0x9f000) is generally also reserved... there is pretty
much always BIOS data structures there.

It sounds like the Nvidia driver is trying to map those, and doing it
incorrectly. -ENVIDIA.

-hpa
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