[coreboot] [v2] r4745 - in trunk/coreboot-v2/src/cpu/intel: socket_PGA370 socket_mPGA479M socket_mPGA604

Stefan Reinauer stepan at coresystems.de
Sat Oct 10 12:10:31 CEST 2009


Peter Stuge wrote:
>> Especially due to microcode it's not possible to make this completely
>> generic: All microcode for all Intel CPUs alone is more than 500kb
>>     
>
> And there's no good reason to do so. All those CPUs are not really
> interchangeable anyway, so it's fine to "only" support the CPUs that
> actually fit on the board. (With or without adapters, like 370/Slot1)
>   
I think for the adapter case it's ok if people have to change the source
code to change the socket of their mainboard manually.
Maybe these adapters are not so common.

>> It's less about grouping CPUs but more about a clean device model.
>> If we want coreboot to be easily understandable, we need to make it
>> reflect what hardware looks like, logically. I think Ron has
>> brought up some pretty good reasons for moving the CPU capabilities
>> into the sockets (Which is a hack we need because of romcc -
>>     
>
> Hm. You just explained how the socket already controls which CPU code
> is included - so basically CPU capabilities are already determined by
> sockets. I don't think anything is principally wrong with letting the
> socket also control the code produced by romcc?
>   
Yes, if the socket decided whether to enable MMX or SSE for romcc, it
should also set CFLAGS for the romcc calls accordingly, so we keep stuff
logically together.


>> Enabling MMX and SSE per socket is only needed because romcc ne
>> to work without cache or memory.
>>     
>
> So far that's the only use, but that can change of course.
I don't think it can. Nor should it. Any other use of SSE or MMX in the
firmware would be a very bad move.
> Anyway, is
> the problem that these hardware features are described in Kconfig, or
> that Kconfig bools are like wired-or, so that any one means true,
> when it should instead be wired-and, so that all must be true.
>   
Yes. That keeps us from moving stuff to the CPUs

> Is the Kconfig mod worth it?
>
>   
Changing Kconfig because of romcc? I don't think so.

Stefan

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