Freeze due to performance_cx_lowest=LOW
John Baldwin
jhb at freebsd.org
Thu Jun 1 20:43:11 UTC 2006
On Tuesday 30 May 2006 23:19, Nate Lawson wrote:
> Andriy Gapon wrote:
> > on 29/05/2006 23:10 Nate Lawson said the following:
> >> disable apic (hint.apic.0.disabled="1"). I isolated this a little while
> >> ago to the change to enable LAPIC timer. However, there is currently no
> >> easy way to disable the LAPIC timer with APIC enabled so you have to
> >> disable APIC. jhb@ and I have been discussing how to do this better but
> >> no easy answers apparently.
> >
> > I am not sure what I am talking about, but is it potentially possible to
> > drive timer system by more than one clock, actively using the most
> > precise of them at any particular moment ? So that if LAPIC timer stops
> > i8254 can be used instead.
>
> That requires mixed mode delivery -- i8254 on legacy PIC irq and APIC
> mode for other interrupts. jhb@ just killed this and isn't eager to add
> it back. I'll let him explain if he has more to add.
Namely that it is unreliable and expressly forbidden by the ACPI spec.
--
John Baldwin
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