Re: [PATCH] x86: apic - unify APIC_DIVISOR

Maciej W. Rozycki
2008-10-10T19:18:00Z

On Fri, 10 Oct 2008, Venki Pallipadi wrote:

> If there is no pressing reason to change the initial calibration value, how
> about the simple patch below.
>
> The 10^9 value that is used for 100 mS calibration time is pretty big as
> tglx's comment points out. We will only underflow it if there is a
> bus clock running at 10 GHz * 16 = 160 Ghz.
>
> This way we will not fix something that is not really broken today and will not
> break in foreseeable future.

I am fine with this version too. The initial count value used for
calibration is really arbitrary -- for all the systems I have seen the
APIC clock was in the sub-MHz range. And 64-bit hardware runs both code
variations so the choice of what the 32-bit code version does is
appropriate as it is also known to work with 32-bit equipment.

Maciej