Re: [PATCH] Display Intel Dynamic Acceleration feature in /proc/cpuinfo

H. Peter Anvin
2007-05-24T22:52:10Z

Dave Jones wrote:
> On Thu, May 24, 2007 at 03:14:39PM -0700, H. Peter Anvin wrote:
>
> > pbe collides with abuse by at least two vendors (AMD and
> > Cyrix/Centaur/VIA) of this bit for 3DNow.
>
> Unless I'm mistaken,
>
> pbe comes from cpuid level 1
>
> 3dnow comes from cpuid level 0x80000001
> though I did notice that amd have it in edx, whilst via have it in ecx
> curiously.

edx is correct.

What you're describing is correct for later-level AMD/Cyrix chips,
however, when 3DNow! was first introduced they foolishly squatted on the
Intel-assigned CPUID flags.

However, I have audited all the vendor initialization paths, and we kill
off that CPUID bit in all the places that matter.

-hpa