> > reg00: base=0x000000000 (    0MB), size=  512MB, count=1: write-back
> > reg01: base=0x020000000 (  512MB), size=    1MB, count=1: write-back
> > reg02: base=0x020000000 (  512MB), size=    1MB, count=1: uncachable
> > reg03: base=0x0f2000000 ( 3872MB), size=   32MB, count=2: write-combining
> > reg04: base=0x0f8000000 ( 3968MB), size=   64MB, count=1: write-combining

> that is original setting by BIOS.
> it should be ok.
> if you like, could try to enable
> 
> CONFIG_MTRR=y
> CONFIG_MTRR_SANITIZER=y
> CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT=1
> CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT=1
> 
> it could do the clean up for you.

Thank you, it did clean it up:

reg00: base=0x000000000 (    0MB), size=  512MB, count=1: write-back
reg01: base=0x0f2000000 ( 3872MB), size=   32MB, count=2: write-combining
reg02: base=0x0f8000000 ( 3968MB), size=   64MB, count=1: write-combining

and it removed the overlapping MTRR-s altogether since there was no RAM 
described t be here. Seems to work fine.

-- 
Meelis Roos (mroos@linux.ee)