Memory controller not showing half of the memory?

["Naik, Avadhut" <avadnaik@amd.com>]

On 4/1/2025 06:44, mailinglist@reox.at wrote:
> 
> 
> Am 28.03.2025 um 16:24 schrieb Borislav Petkov:
>> On Thu, Mar 20, 2025 at 11:38:58AM +0200, Žilvinas Žaltiena wrote:
>>> Hello,
>>>
>>> I am also having this "half" memory problem - EDAC is showing 48GB instead
>>> of 96GB, however otherwise whole 96GB are usable by OS.
>>
>> Both of y'all folks encountering this issue, care to run the below patch?
>>
>> https://lore.kernel.org/all/20250327210718.1640762-1-avadhut.naik@amd.com/
>>
>> Thx.
>>
> 
> I tried to apply it on the current Bookworm Backports kernel (6.12.12) - which seemed to work but I still get the same output, i.e., 32GB out of 64GB of RAM.
> 

Think we are mixing up issues here. So, to clarify, there are two issues currently being worked on in the
amd64_edac module.

1. For Family 19h Models 70h-7Fh all UMCs are not enumerated by the module. 4 are present but only 2 are
enumerated. Currently, required approvals are being sought to upstream the fix. I think this is the issue
being encountered by Sebastian from the dmesg logs and lshw output provided in this thread.

2. For calculating DIMM sizes, the module does not consider both Address Mask and Address Mask Secondary
registers. Consequently, for non-power-of-2 DIMMs, the memory size logged by the module is inaccurate. I
think this is the issue being encountered by Žilvinas.

The patch that Boris asked you folks to try out fixes the second issue. Fix for the first issue has not
yet been submitted.

> I may not have built the kernel correct though... I did not had an environment to do that and just set one up. Or do I need a newer kernel version to apply the patch to? Sorry for the noob questions...
> 
> Best,
> Sebastian

-- 
Thanks,
Avadhut Naik