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Andrey Falko wrote: |
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> Ahh I see. I don't know much about MTRR...all I know is that you can |
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> adjust them via grub: |
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> http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?part=1&chap=10 |
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Hmm... I missed that one. Thanks. |
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My grub kernel command line (which I haven't given much thought to since |
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it's inception many years ago): |
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root=/dev/sda2 vga=804 video=vesafb:1280x1024-32@85,mtrr:3,ywrap |
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This should tell vesafb to set MTRR to use write-combining (for which |
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memory region, I don't know), but it doesn't work for me, for some |
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reason. All of my mem (under X) is set to write-back with the exception |
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of 1Mb set to uncacheable. My other computer has even stranger settings |
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and the kernel log complains about MTRR settings not correctly setup (it |
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states that the BIOS probably doesn't init's both cores). |
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> . You probably read this already: |
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> http://en.wikipedia.org/wiki/Memory_Type_Range_Registers |
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Yep. Here's a few more if you (or anyone else) find this interesting: |
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http://en.wikipedia.org/wiki/Write-combining |
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http://en.wikipedia.org/wiki/Cache |
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Basically the MTRR (and PAT) determines how the processor (and it's |
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cache(s)) accesses the memory regions (in the MTRR). Xorg supposedly |
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should set up the MTRR when it starts. |
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> Yeh, I have Nvidia cards, so I guess ATI is different. |
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Perhaps. |
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Thanks again! It's always good to weather one's thoughts on a subject... |
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This just got me thinking. I'll investigate what the MTRR settings look |
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like before the display manager starts... |
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Best regards |
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Peter K |
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-- |
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