[LinuxBIOS] addr_offset help

Joseph Smith joe at smittys.pointclark.net
Sat Sep 1 00:37:54 CEST 2007

Quoting Corey Osgood <corey.osgood at gmail.com>:

> Joseph Smith wrote:
>> Can someone explain the significance of the  addr_offset variable in
>> raminit.c on the i440bx and i82810? Also why is this set to 0x1d0 for
>> the Mode register set (MRS)?
>> Thanks - Joe
> MRS is a setting within the ram that's set by reading from a certain
> location while the northbridge is in MRS mode. It essentially tells the
> ram what timings to run at. For the most part, the only values you'll
> ever need for SDRAM are 0x1d0 for CL3 and 0x150 for CL2, but DDR and
> DDR2 make more advanced use of MRS and E(xtended)MRS. Read the JEDEC
> standard for more info.
> -Corey
Thanks Corey, that makes sense. Not sure how it tells the memory what  
timings to run at though. Does it tell the northbridge what timings to  
run at?

Thanks - Joe

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