On 5/15/2012 12:26 PM, Seyyed Mohtadin Hashemi wrote:
> On Tue, May 15, 2012 at 4:30 AM, Henrique de Moraes Holschuh <
hmh@debian.org
>> wrote:
>
>> On Mon, 14 May 2012, Stan Hoeppner wrote:
>>> On 5/13/2012 7:02 PM, Henrique de Moraes Holschuh wrote:
>>>> On Fri, 11 May 2012, Seyyed Mohtadin Hashemi wrote:
>>>>> On 5/10/2012 1:16 PM, Stan Hoeppner 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.
>>>
>>> I'm not surprised I was correct WRT a BIOS bug, but I am a little
>>> embarrassed I didn't know and suggest this would be reported in dmesg.
>>> I admit I just don't see this very often--this being the 1st time
>>> actually seeing this WARNING.
>>
>> Well, it is the first time I've seen a BIOS screw it up so badly as to
>> have someone lose 61GiB of RAM over 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:
>>>
>>> Yep. In vanilla 3.2.6 it's selected by default in menuconfig, and you
>>> can't un-select it.
>>
>> We _really_ need to have that enabled by default on the Debian kernels
>> IMO, if we don't enable it already.
>>
>> --
>> "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
>>
>
> Thank you for the tips Henrique and Stan, unfortunately i don't have time
> to build/test new kernels this week because i have to finish my thesis. I
> will have time next week to look at it and report back the results.