Interesting Compile Problem - 2.6 Kernel

[Steve Jardine]

All,

    I have a real strange one to relate to you.

    System: 4 Xeon Processor, Dual Core with Hyperthreading
            PCI-E, PCI backplane

    System A: CPU Family 15, Model 4, Stepping 1
    System B: CPU Family 15, Model 4, Stepping 8

    Now, System A compiles fine with the processor type of Pentium 4/Xeon, and SMP/Multicasting set. All 8 cores show up without a problem. Boots perfectly.

    However, System B with the same settings cannot boot. Kernel panics when attempting to boot.

    What I have found out: Stepping 1 is a true Pentium 4 core, works as advertised. System B can *only* have the kernel compiled as a CPU Type of Pentium PRO. It shows all 8 cores and will perform hyperthreading if the flags are set in the kernel configuration with the CPU type of Pentium PRO.

    I have read that the stepping 8 Xeon does not have 64 bit cvapability for processing or for I/O to/from the cores. It works the way I compiled it, but I would like to know why it must be this way?? 

    Anyone have any ideas?   


    Steve
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