# UVESAFB: bootsplash much slower with mtrr:2 than mtrr:3...

## VinzC

[... is it normal?]

Hi all.

I've setup bootsplash with uvesafb but I noticed it's much slower with mtrr:2 than with mtrr:3. By slower I mean updating the splash screen while booting. For instance I can clearly see the screen being filled (from top to down) when the splash is first displayed. And fading takes much longer. Just refreshing the splash screen is slow.

I switched to mtrr:2 because I had spotted warning messages such as 

```
mtrr: type mismatch for e0000000,8000000 old: write-back new: write-combining
```

 as explained in the documentation. However bootsplash was much faster.

Is that behaviour normal or have I missed something?

My video card is an nVidia GeForce GTS 450.

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## chithanh

On modern systems, MTRR use is often reduced in favor of PAT. So BIOS writers pay less attention to it than they used to. Most likely the issue you are seeing is due to BIOS bugs.

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## VinzC

Thanks chithanh.

 *chithanh wrote:*   

> On modern systems, MTRR use is often reduced in favor of PAT. So BIOS writers pay less attention to it than they used to. Most likely the issue you are seeing is due to BIOS bugs.

 

I tried booting my kernel without any mtrr argument (i.e. video=uvesafb:ywrap,1280x1024-32) and now the error message is gone. I can see PAT is used indeed. Thanks for the tip.

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