Re: Which CPU for VIA C7/Esther?

[Simon Arlott <simon@arlott.org>]

On 12/02/07 20:16, Dave Jones wrote:
> On Mon, Feb 12, 2007 at 02:14:41PM -0500, Kyle McMartin wrote:
>  > On Mon, Feb 12, 2007 at 06:37:38PM +0100, Mark de Vries wrote:
>  > > I've been googeling for about an hour now and can't find an answer to:
>  > > What type of CPU should I select when compiling a recent 2.6 kernel if I
>  > > have a VIA Esther CPU?
>  > 
>  > > stepping        : 9
>  > 
>  > config MVIAC3_2
>  >         bool "VIA C3-2 (Nehemiah)"
>  >         help
>  >           Select this for a VIA C3 "Nehemiah". Selecting this enables usage
>  >           of SSE and tells gcc to treat the CPU as a 686.
>  >           Note, this kernel will not boot on older (pre model 9) C3s.
>  > 
>  > Is the one you want, I believe.
> 
> The C7 doesn't seem to care much which you optimise it for.
> Any of the 686 options should work just fine, but MVIAC3_2 is no
> worse than any of the others.
> 

MVIAC3_2 doesn't enable X86_GOOD_APIC, try M686 (Pentium-Pro) - but that won't enable MMX and SSE (via -march=c3-2).
These CPUs support SSE2 too... there should probably be an option for C7 that passes 686/mmx/sse/sse2 to gcc. (The c3-2 option could even cause gcc to alter code for the C3-2 that's not necessary for the C7, but I've not checked what else gcc does with -march=c3-2).

Also, for the C7 you'll want CRYPTO_DEV_PADLOCK_* (Hardware Crypto Devices, Support for VIA PadLock ACE) and HW_RANDOM_VIA (VIA HW Random Number Generator support).

-- 
Simon Arlott

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