Re: Only 3.6gb of 64gb RAM recognized by 64bit squeeze
On Fri, 11 May 2012, Seyyed Mohtadin Hashemi wrote:
> > If this doesn't fix the issue, and memtest and other utils can see all
> > 64GB just fine, then I'd say you're dealing with a BIOS bug.
>
> The very top of /var/log/dmesg has the kernel debug output about the memory
> map. It might well tell us very quickly who is the culprit, if the user
> with the problem can post it for the best working case and the non-working
> [ 0.000000] e820 update range: 00000000e0000000 - 000000101f000000
> (usable) ==> (reserved)
> [ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory,
> losing 61936MB of RAM.
There you have it.
Any of the latest versions of the longterm kernels (2.6.32, 3.0), or
latest 3.2 should be able to repair MTRRs properly, but you have to
compile the kernel with that option enabled. It might be already
available, but not enabled by default. In that case, this might help
you:
http://hawknotes.blogspot.com.br/2010/05/ubuntu-1004-fixing-mtrr-errors.html
and
http://phoronix.com/forums/showthread.php?16940-bad-MTRR-setup-according-to-DRM&p=74238#post74238
File a bug with the mainboard vendor, anyway. Give them the Linux dmesg
bootlog you sent me, up to and including the warning above, so that they
know what they're doing wrong.
Also, run BITS on that mainboard and complain to the motherboard vendor
about anything BITS reports as broken.
http://www.biosbits.org/
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
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