[coreboot] How to handle vbt.bin

[Peter Stuge]

Nico Huber wrote:
> VBT is mostly nee- ded for Windows and who knows what the driver
> does there; when it comes to Linux, we should at least try to talk
> some sense into the developer's to tell us which information they
> really need.

I wouldn't assume that they know in advance - I think they may just
have to deal with whatever is produced by hardware engineering.


> > Do you know where documentation can be found?
> 
> The most comprehensive documentation I know about the various sub-tables
> and how they are organized is the i915 Linux driver code that reads it.
> There are also per-platform description files that tell a "binary modi-
> fication program" by Intel what bit is what. You can find them sometimes
> along the FSP releases (e.g. [1]; 9972 lines, yeah!).

BSF describes the data structure perfectly. (What a fun file format! :)

Zoran's Wikipedia article links to this, which clears up the binary format:

https://cgit.freedesktop.org/xorg/app/intel-gpu-tools/tree/tools/intel_vbt_decode.c


> If somebody really wants to digest complete VBTs, I think the best shot
> would be to translate these description files into something nicer and
> have a tool like bincfg [2] to translate human readable VBTs into binary
> ones (based on the description).

That makes perfect sense.


A human readable VBT representation has a clear place in the mainboard
directory for all applicable platforms. That would be a good thing.

I don't know if the entire data structure must neccessarily be integrated
into Kconfig, but maybe if someone has a lot of free time... :)


//Peter