topic Such a information could be in Software Tuning, Performance Optimization & Platform Monitoring

Overwrite Locked Bits in a Memory Controller

sarkar__saptarshi — Tue, 19 Nov 2013 00:34:21 GMT

Hi Everyone,

I am in dire need of overwriting a locked register named DIMM Memory Technology register (link ).

My objective is to disable a rank selectively.

http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e5-1600-2600-vol-2-datasheet.pdf

Page No 427.

The field positions are marked as RW-LB. Indicating that one can bypass them provided lock bypass

bits are enabled. I am very sure that the BIOS does write to those fields because I can observe the

values being changed each time I change my memory configuration by a difeerent DIMM layout.

My problem is that nowehere have I found a way to do so. Even the manual just mentions it but

does not describe it.

One post having the same question has been unanswered for a long time. If its confidential,

I would welcome if any one would let me know that or otherwise any help will be deeply appreciated

Saptarshi

Such a information could be

Bernard — Sun, 24 Nov 2013 08:03:36 GMT

Such a information could be classified under NDA and provided only for kernel/BIOS developers.

Hello Saptarshi,

Patrick_F_Intel1 — Fri, 24 Jan 2014 15:53:17 GMT

Hello Saptarshi,

I don't know of any way to override the bits if they are locked. Usually if someone needs to do this sort of thing, they have to get BIOS folks to create a special BIOS that doesn't lock the bits or maybe they add a BIOS boot setup screen which allows you to change the settings at boot time.

Getting a special bios is a very difficult thing to do and requires a lot of justification.
Pat