Re: [PATCH 5/8] p4_clockmod: detect speed without relying on cpu_khz or user input

[Dominik Brodowski <linux@brodo.de>]

On Fri, Nov 21, 2003 at 02:26:13AM +0000, Dave Jones wrote:
> On Thu, Nov 20, 2003 at 07:33:35PM +0100, Dominik Brodowski wrote:
>  > On Wed, Nov 19, 2003 at 07:09:46PM +0000, Dave Jones wrote:
>  > > 
>  > > patch 4/8 introduced what seems to be the exact same code in the speedstep-lib.
>  > > Perhaps it belongs in an fsb.o instead that they can both share ?
>  > > I don't mind duplicating it twice in object code, but having two copies
>  > > in the source seems a bit silly.
>  > 
>  > Usually, I agree to this topic. However, I don't want to create just another
>  > file for just this function, and it doesn't belong to speedstep-lib either
>  > as a plain p4 isn't a valid processor for speedstep-lib. So I'd prefer to
>  > have this source code duplication as an exception here.
> 
> Your call. I'm just concerned with the maintainence effort as this
> routine grows.
> 
> As a sidenote, this could be useful outside of cpufreq at some point too.
> Alan tried adding 'overclocking detection' using these registers a while
> back. It is very difficult to get correct however, so it never came to
> anything.  If we took the "perfect is the enemy of 'good enough'" approach
> and just did these checks for cpus we knew we do it correctly on, this
> would become feasable to pull off for 2.7.

Well, for Intel P3s and P4s the MSRs are eithre documented or reverse-
engineered quite well, so it should be something good to do in 2.7.[*]

	Dominik

[*] which will hopefully be soon!