Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80on some AMD64x2 laptops, etc.

[Pavel Machek]

On Fri 2007-12-14 15:23:55, Ingo Molnar wrote:
> 
> * Rene Herman <rene.herman@xxxxxxxxx> wrote:
> 
> > --- a/init/main.c
> > +++ b/init/main.c
> > @@ -229,10 +229,9 @@ static int __init obsolete_checksetup(char *line)
> >  }
> >
> >  /*
> > - * This should be approx 2 Bo*oMips to start (note initial shift), and will
> > - * still work even if initially too large, it will just take slightly longer
> > + * Initial value roughly corresponds to a 1 GHz CPU
> >   */
> > -unsigned long loops_per_jiffy = (1<<12);
> > +unsigned long loops_per_jiffy = 1000000000 / HZ;
> >
> >  EXPORT_SYMBOL(loops_per_jiffy);
> 
> this is a factor of ~2400 increase - this will take an eternity to boot 
> on any older CPU.

I don't think we are using outb_p before loops_per_jiffy are
initialized -- I believe I'd see oopsen if we did. Factor 2400
increase is bad, but if it only converts 10x 1usec delay into 10x
24msec delay, it is not _that_ bad.
								Pavel
-- 
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