* Len Brown <l...@kernel.org> wrote:
> From: Len Brown <len.br...@intel.com>
>
> Modern processor familes are on a white-list to remove
> the costly cpu_init_udelay 10000. Unknown processor families
> get the traditional 10ms delay in cpu_up().
>
> This seemed more efficient than forcing modern processors
> to exhaustively search a black-list having all the old
> processor families that should have a 10ms delay.
> For not only are new processor familes infrequently added,
> the white list also allows a delay other than 0, if needed.
> static unsigned int init_udelay = UDELAY_10MS_DEFAULT;
>
> +static const struct x86_cpu_id init_udelay_ids[] = {
> + { X86_VENDOR_INTEL, 0x6, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0x16, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0x15, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0x14, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0x12, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0x11, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0x10, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + { X86_VENDOR_AMD, 0xF, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> + {}
> +};
So since especially AMD likes to iterate the family upwards, why not
make this a simple open ended check:
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
boot_cpu_data.x86 >= 6 ||
boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
boot_cpu_data.x86 >= 15) {
... 0 delay ...
}
... which is much smaller and more future proof?
Thanks,
Ingo
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