[coreboot] Re: T440P: Unable to initialize memory speeds above 1600 MT/s

[ad-min]

After cherry picking a few dozen commits of the brilliant mythbk and following 
his suggestions I was able to get it up and running.

https://github.com/archfan/coreboot/commit/bd3e5cf5c8277dbb286ec4234e0355afe25bb25d

> 1600MT/s is what the controller officially supports. Anything faster is
overclocking and the mrc.bin likely does not support that.

Correct. There is a hard coded limit of 1600 MT/s in the mrc.bin.
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[coreboot] Re: T440P: Unable to initialize memory speeds above 1600 MT/s

[Arthur Heymans]

ad-...@mailbox.org writes:

> I just bought a pair of HyperX DDR3L-2133 CL11 memory. They are supported and 
> run fine at 2133 MT/s with the original Lenovo firmware.
>

> However Coreboot only registers them at 1600 MT/s. 
>
> Changing the value of .max_ddr3_freq to 2133 in 
> src/mainboard/lenovo/t440p/romstage.c leads to a bricked notebook. A beeping 
> sound occurs, regardless of the installed memory type (1600 or 2133).
>

Looking at src/northbridge/intel/haswell/pei_data.h The only valid
values are 800, 1067, 1333, 1600 for the mrc.bin. The sandybridge code
with a similar PEI/mrc.bin is better at guarding against invalid
values. Maybe that code should be adapted to haswell.

1600MT/s is what the controller officially supports. Anything faster is
overclocking and the mrc.bin likely does not support that.

-- 
Arthur Heymans
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