Re: [tip:x86/mm] x86/mm/mtrr: Clean up mtrr_type_lookup()

Borislav Petkov
2015-08-01T16:33:16Z

On Sat, Aug 01, 2015 at 04:28:20PM +0200, Luis R. Rodriguez wrote:
> I need to update this documentation to remove set_memory_wc() there as we've
> learned with the MTRR --> PAT conversion that set_memory_wc() cannot be used on
> IO memory, it can only be used for RAM. I am not sure if I would call it being
> broken that you cannot use set_memory_*() for IO memory that may have been by
> design.

Well, it doesn't really make sense to write-combine IO memory, does it?
My simplistic impression is that an IO range behind which there's a
device, cannot stomach any caching of IO as all commands/data accesses
need to happen as they get issued...

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Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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