[coreboot] Crazy Intel graphics mtrr
joe at settoplinux.org
joe at settoplinux.org
Thu Apr 17 06:21:10 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)
>
>YH
>
Hmm, so it all adds up but, what is the need for 3 different mtrr's instead of one? Also, what about this:
>> 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?
--
Thanks,
Joseph Smith
Set-Top-Linux
www.settoplinux.org
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