[coreboot] EP80579 Mainboard support

Ed Swierk eswierk at aristanetworks.com
Wed Jun 24 16:29:02 CEST 2009

On Wed, Jun 24, 2009 at 6:36 AM, Arnaud Maye<arnaud.maye at 4dsp.com> wrote:
> I've tried a reverse engineer approach. Plug a DIMM into the system and
> launch Linux with the
> legacy BIOS. lspci -xxx then shows me the IMCH BAR and implicitly the
> settings doctored by the
> legacy BIOS. The first try I've done was to try the r-e DRT0/DRT1 in the
> coreboot RAM init code.
> Not much differences so far. But anyway I've seen quite a lot of difference
> around the ODT register
> and such. So there is still some hope.

Have you tried 2T timing? This causes the memory controller to wait an
extra cycle before sending a command. The delay can compensate for
slight misconfiguration of other signal timing settings so it's a good
place to start.

Also try different RCOMP values. I have no idea what RCOMP is but I
remember having to tweak it to get the memory to behave.


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