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

[Mick <michaelkintzios@gmail.com>]

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On Thursday 19 August 2010 15:47:46 Bill Longman wrote:
> On 08/19/2010 04:37 AM, Walter Dnes wrote:
> > On Mon, Aug 16, 2010 at 05:55:04PM -0500, Paul Hartman wrote
> > 
> >> 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:
> >   I'm using the Intel driver, which doesn't have those settings.  And
> > 
> > no, I do not want to drop down to a generic VESA driver with no hardware
> > acceleration.  Some more Google searching has turned up a lead.
> > Apparently, it's possible to manually set the mtrr's, using cat and echo
> > with /proc/mtrr
> > 
> >   According to "lspci -v", my integrated graphics chip has
> >   
> >         Memory at fb800000 (64-bit, non-prefetchable) [size=4M]
> >         Memory at d0000000 (64-bit, prefetchable) [size=256M]
> >   
> >   My mtrr setup, however, shows up like so...
> > 
> > waltdnes@i3 ~ $ cat /proc/mtrr
> > reg00: base=0x000000000 (    0MB), size= 8192MB, count=1: write-back
> > reg01: base=0x200000000 ( 8192MB), size= 1024MB, count=1: write-back
> > reg02: base=0x0c0000000 ( 3072MB), size= 1024MB, count=1: uncachable
> > reg03: base=0x0b4000000 ( 2880MB), size=   64MB, count=1: uncachable
> > reg04: base=0x0b8000000 ( 2944MB), size=  128MB, count=1: uncachable
> > reg05: base=0x1fc000000 ( 8128MB), size=   64MB, count=1: uncachable
> > 
> >   I'll read up more on how to set it up manually.  One thing that has my
> > 
> > curiousity right now... how come there's a gig of ram in write-back mode
> > *STARTING* at 8 gigs, and ending at 9 gigs minus 1 byte, when I only
> > have 8 gigs of ram in total?
> 
> You might want to have a look in your kernel Documentation directory.
> There's a file x86/mtrr.txt that gives you some info. And lots in the fb
> subdirectory. You can probably find some other info there, too. There's
> lots of the dreaded MTRR info in the kernel_parameters.txt file, so you
> can setup the MTRRs at boot time.

I've read as much as I could find, but the whole hexadecimal thing has me 
overwhelmed  O_O

I think my mtrr is OK, but I do not understand this enough to know if it would 
benefit from manual configuration.

Walter please break it into small change for me when you sort out yours - you 
could contact me off list if this is getting too O/T.
-- 
Regards,
Mick

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