[gentoo-user] Re: dmesg warning about mtrr: type mismatch and allocation failed

[walt <w41ter@gmail.com>]

On 08/15/2010 04:27 PM, Walter Dnes 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?
>
> [    0.519939] Linux agpgart interface v0.103
> [    0.520016] agpgart-intel 0000:00:00.0: Intel HD Graphics Chipset
> [    0.520842] agpgart-intel 0000:00:00.0: detected 131068K stolen memory
> [    0.580462] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000

Does your BIOS let you set the AGP aperture manually?  Couldn't hurt to make
it bigger if you're able.  The comment about 'stolen memory' sounds a bit evil ;)


> [    0.608643] mtrr: type mismatch for d0000000,10000000 old: write-back new: write-combining
> [    0.608725] [drm] MTRR allocation failed.  Graphics performance may suffer.

Do you have MTRR support in your linux kernel?  It was selected automatically in
my SMP kernel config, so I didn't have a choice.

> [    0.946741] Console: switching to colour frame buffer device 240x75
> [    0.952156] fb0: inteldrmfb frame buffer device

I'm wondering if console framebuffer support is really necessary for Intel
graphics chips, I dunno.  You could try disabling it in your kernel config
to see if it make any difference.

I'm assuming that all of the dmesg stuff came from boot time, right?  Does your
/var/cache/Xorg.0.log have any suspicious messages?  I'm assuming your X works
correctly?  Or not.