Re: [PATCH] Blacklist Dell Optiplex 320 from using the HPET

Andi Kleen
2007-05-05T22:05:50Z

On Saturday 05 May 2007 21:15:01 Thomas Gleixner wrote:
> On Sat, 2007-05-05 at 19:24 +0200, Andi Kleen wrote:
> > > if (!is_hpet_capable())
> > > @@ -278,6 +279,14 @@ int __init hpet_enable(void)
> > > /* Start the counter */
> > > hpet_start_counter();
> > >
> > > + /* Verify whether hpet counter works */
> > > + t1 = hpet_read();
> > > + udelay(50);
> >
> > Are you sure udelay is calibrated at this point? I didn't think so.
> > In fact it needs the external clocks and it's a chicken and egg problem.
>
> Oops. You are right. OTOH it does not matter whether it is accurate or
> not.

It might be very short if you're very unlucky and the CPU is fast
and then trigger the check incorrectly.

-Andi