[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.


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