Re: Cyrix 6x86MX and Centaur C6 CPUs in 2.1.102

Martin Mares (
Wed, 20 May 1998 16:09:38 +0200


> c) The code that shows Cyrix CPU steppings does not conform to Cyrix
> stepping numbering. 6x86MX steppings are documented as 1.3, 1.4, 1.5,
> 1.6, etc... in both the Cyrix/NS and IBM documentation, _not_ 0.3, 0.4,
> 0.5, 0.6 as the present Linux kernel code would have it.
> A similar mistake is done for K6 steppings, which in the AMD
> documentation are described as steppings A, B, C.
> This causes confusion with users that do "cat /proc/cpuinfo" and can't
> figure out what CPU stepping they have. So I wish you could get it
> right.

I didn't implement it in the original CPU detection code as it seemed very
hairy to me and I didn't like to substantially enlarge the code by lots of
weird stepping naming conversions.

Anyway, just send me a patch :-)

> d) Also bug reporting in /proc/cpuinfo. Everytime I see reported that my
> 6x86(L,MX) or K6 machines don't have the F00F bug, I wonder what use is
> there to report a bug that simply is _not_ there and couldn't be. This
> also confuses most Linux users.

Actually, this would be a bit confusing as you won't have any way to
distinguish between "this CPU cannot have this bug" and "this kernel doesn't
detect this bug".

Have a nice fortnight

Martin `MJ' Mares   <>
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
"All computers run at the same speed... with the power off."

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