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Revision as of 16:31, 9 May 2007 by Hawke (talk | contribs)
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The wiki is being retired!

Documentation is now handled by the same processes we use for code: Add something to the Documentation/ directory in the coreboot repo, and it will be rendered to Contributions welcome!

Current problems

  • MA map type is set incorrectly for some types of DIMM. In progress.
  • some memory errors persist even once the MA map type is set correctly; This may be caused by LB passing an incorrect e820 memory map. This conclusion is based on memtest86 passing all tests when "Probed" is selected for memory sizing, but failing when "BIOS-Std" or "BIOS-All" is selected.

MA Map Types

The values for MA map type refer to bits 15-13, 7-5, and 3-1 of offset 0x59-0x58 of the VT8601A host bridge. See the VT8601/PLE133 data sheet for details. All values other than 0xx and 100 are documented as "reserved (do not program)"

Values determined by testing various modules with the factory BIOS.
DIMM size Row Density (SPD 31) Width (SPD 13) Rows(SPD 5) MA map type
512MB 256MB 8 2 0xe (111)
256MB 128MB 16 2 0xc (110)
128MB 128MB 16 1 0xc (110)
128MB 64MB 8 2 0x8 (100)
64MB 64MB 8 1 0x8 (100)