[LinuxBIOS] Please explain why is some hardware not supported even though it runs fine in linux

[joe at smittys.pointclark.net]

Quoting Stefan Reinauer <stepan at coresystems.de>:

> * Al Boldi <a1426z at gawab.com> [070309 14:25]:
>> Are the datasheets enough to get the board supported by LinuxBIOS?
>>
>> If so, which board has been supported by only relying on the datasheets?
>
> This depends on the data sheets. The AMD64 (AMD8111/AMD8131) port has
> completely been developed from publicly available data sheets (including
> the publically available bios and kernel developers guide).
>
> Very often, there are no publically available data sheets, or the
> publically available versions are censored and do not contain the
> required information to write a BIOS/Firmware. This is the case for
> basically all modern Intel chipsets.
>
>> Also, the factory bios contains a lot of ram timing info; can't this
>> be used to get a generic/blind LinuxBIOS to init ram, and then payload
>> from flash?
>
> The ram timing info is stored on the RAM modules themselfes, in a small
> chip called SPD-ROM (Serial Presence Detect). The BIOS has to look at
> each single RAM module and find out a common denominator that works with
> all modules used in the system.
>
> Stefan
>
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Correct me if I am wrong, can't the SPD-ROM be read through the i2c  
(smbus). I know, if you have a supported super IO you can use  
lmsensors to read the SPD-ROM. Would that be helpful in this case?

Thanks - Joe