[coreboot] Nehalem not booting with two ram sticks

[Andrey Korolyov]

On Tue, Nov 22, 2016 at 3:35 PM, Federico Amedeo Izzo
<federico.izzo42 at gmail.com> wrote:
> Hello,
>
> I have a problem with my ThinkPad X201 (nehalem)
>
> I have two sticks of Samsung 4GB 2Rx8 PC3-10600S (1333MHz)
> When i use only one of them in one of the two slots, the computer boots
> fine,
> but when i use both of them in the two slots, the computer doesn't boot,
> the screen doens't even turn on.
>
> I dumped the logs via EHCI but they seem normal, in fact both the
> working combination and the broken one make 34 or so iterations of
> Timings dumping,
> but then the working conf. start booting, while the broken one freezes
> without printing error messages on the EHCI.
>
> I have tried adding more `printk` calls in
> `src/northbridge/intel/nehalem/raminit.c`
> but ended up in a brick, probably because i slowed down the
> initialization too much.
>
> I attach three EHCI logs:
> - the first stick in the first slot: working
> - the second stick in the second slot: working
> - both stick inserted: not working
>
> Also i find difficult to understand the code in `raminit.c` of nehalem
> because it lacks almost completely of comments, with respect to
> raminit.c of sandybridge for example.

I`ve seen simular issue on my x201(t), the workaround could be a
hardcoded SPD limitation from above for memory clock speed. Using
different memory sticks (Kingstons rather than Samsungs) is 'solving'
problem as well. I`ve not paid necessary attention to the problem at
the time, so if you have some spare cycles, you could possibly want to
figure out right SPD settings. The simplest way is to use decode-dimms
from i2c-tools or CPU-z and to compare vendor`s settings with single-
and dual-dimm setups and coreboot`s with a single dimm.