mtrr funnies

[Robin Laing]

Wolfgang S. Rupprecht wrote:
> I've got a motherboard with a fairly new chipset (Asus M3A78T
> w. AMD/ATI 790GX) and I'm seeing a funny MTRR setting.  I have 8GB
> memory and am running a 64-bit kernel, but I'm only seeing ~4GB
> mentioned in the MTRR's.  Is this a bug?  Do I need to add the upper
> 4+GB by hand?
> 
>     $ cat /proc/mtrr
>     reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1
>     reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
>     reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
>     reg03: base=0xd0000000 (3328MB), size= 256MB: write-combining, count=1
> 
> It does seem like the kernel sees the whole memory, at least at times,
> but it isn't clear if that high memory is being cached the right way.
> 
>     Oct  7 10:54:30 poblano kernel: Memory: 7678940k/8650752k available (2699k kernel code, 184672k reserved, 1485k data, 980k init)
> 
> -wolfgang

Check the ASUS site for a BIOS update.  I had this issue on a new 
motherboard earlier this year.  There were BIOS updates to fix memory 
issues.

My Motherboard recognized the memory but it would keep crashing.  It 
could be a communications issue.

-- 
Robin Laing