[coreboot] Crazy Intel graphics mtrr

yhlu yinghailu at gmail.com
Thu Apr 17 04:08:00 CEST 2008

On Wed, Apr 16, 2008 at 5:03 PM,  <joe at settoplinux.org> wrote:
> Hello,
>  I am noticing some X problems (slow, crashes once and a while) on the RCA RM4100. I think this is related to the crazy way coreboot setup the mtrr. For some reason when the Intel onboard graphics are enabled, coreboot sets up this crazy looking mtrr. I don't think they should all be write-back? Isn't write-combining faster for graphics? Does it need to have a uncachable area?

that is normal.

>  reg00: base=0x00000000 (   0MB), size=  64MB: write-back, count=1
>  reg01: base=0x04000000 (  64MB), size=  32MB: write-back, count=1
>  reg02: base=0x06000000 (  96MB), size=  16MB: write-back, count=1
>  reg03: base=0x07000000 ( 112MB), size=   8MB: write-back, count=1
>  reg00: base=0x07800000 ( 120MB), size=   8MB: uncachable, count=1
>  reg01: base=0x00000000 (   0MB), size= 128MB: write-back, count=1

and old kernel like previous one
64+32+16+8 == (128 - 8)


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