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    SubjectRe: Bug on 2.6.26 - x86 VIA Nehemiah CentaurHauls processor cannot boot
    H. Peter Anvin wrote:
    > Jeff Garzik wrote:
    >>> Thanks for taking a look at this. So well, it would be a
    >>> misconfiguration bug by the distribution then to try to support a
    >>> generic 686 kernel wihtout GENERIC then.
    >> Well, it may be intentional -- some distros simply exclude support for
    >> the lower-volume VIA processors, since that might imply building their
    >> "generic 686 kernel" sans CMOV and some other instructions, and
    >> changing the compiler's instruction scheduling to something less
    >> optimal for the majority. :/
    > X86_GENERIC shouldn't disable CMOV?

    I said "generic 686 kernel" not a specific Kconfig option (for reasons
    stated below), which is a bit different.

    > We're only referring specifically to the family == 6 VIA processors here.

    To be specific, I was merely saying that VIA processors where
    c->x86_model==6 may lack CMOV.

    I have not kept track of what current Kconfig options will set, but in
    the past it was quite easy to build a "generic 686 kernel" that required
    CMOV and thus excluded these VIA processors.

    Distros in the past often wound up intentionally -not- supporting some
    of these VIA processors, because they did not want to create a non-CMOV
    kernel. (This policy obviously excluded older x86 as well)

    If these things have been addressed recently (< 12-18 months) then all good.


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