Re: question about MTRR areas on x86_64

[Andi Kleen]

Markus Lidel <Markus.Lidel@xxxxxxxxxxxxxxxxx> writes:
>
> Could it be because the machine has too much memory, or is there a bug in the I2O driver?

The problem comes from the BIOS who set up reg00 to be overlapping
over other areas. The Linux MTRR driver cannot deal with overlapping
MTRRs, in fact it is sometimes impossible because it could run
out of registers or violate some of the MTRR restrictions.

It's a long standing problem, eventual fix will be to get rid
of MTRRs completely and only use PAT. But it needs a bit more work.

-Andi

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