[LinuxBIOS] addr_offset help

Corey Osgood corey.osgood at gmail.com
Fri Aug 31 22:00:00 CEST 2007

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.


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