On Sun, Aug 15, 2010 at 6:27 PM, Walter Dnes <waltd...@waltdnes.org> wrote:
> I'm running 64-bit Gentoo on an Intel 4-core i3 with an Intel integrated
> graphics controller. An excerpt from dmesg follows, with the video-
> related stuff. Note the two lines that I've split off. They mention
> the mtrr type mismatch and the allocation failure. Is this a problem
> and if so, what do I do about it?
...
> [ 0.608643] mtrr: type mismatch for d0000000,10000000 old: write-back new:
> write-combining
> [ 0.608725] [drm] MTRR allocation failed. Graphics performance may suffer.
I had a similar message, it was there because of the fact that i
specified the wrong (or failed to specify?) mtrr method in my kernel
boot parameters for the framebuffer. I'm using uvesafb and in kernel
documentation (/usr/src/linux/Documentation/fb/uvesafb.txt) it
explains the values and even gives an example of this error and what
to do about it:
<cut>
mtrr:n Setup memory type range registers for the framebuffer
where n:
0 - disabled (equivalent to nomtrr) (default)
1 - uncachable
2 - write-back
3 - write-combining
4 - write-through
If you see the following in dmesg, choose the type that matches
the old one. In this example, use "mtrr:2".
...
mtrr: type mismatch for e0000000,8000000 old: write-back new: write-combining
...
</cut>
After I changed my mtrr setting in grub's config & rebooted, the error
message went away.
HTH :)
