Re: HPET : Legacy Routing Replacement Enable - 3rd try.

[Andi Kleen <ak@muc.de>]

On Thu, Oct 26, 2006 at 11:11:49PM -0700, Om Narasimhan wrote:
> Andi Kleen wrote:
> >>1. HW is LRR capable, HPET ACPI it is 1, timer interrupt is on INT2.
> >>Before the fix: Linux cannot get timer interrupts on INT0, goes for ACPI 
> >>timer.
> >
> >What ACPI timer?  I don't think we have any fallback for int 0.
> Sorry, Mea Culpa, I should have written APIC timer.
> >
> >Not sure what you mean with INT2. Pin2 on ioapic 0 perhaps?
> Yes. PIN2 on IOAPIC #0.
> >
> >>After the fix : Works fine. This is according to hpet spec.
> >
> >On what exact motherboard was that?
> SunFire X4600
> >
> >>To handle case 3, I removed all references to acpi_hpet_lrr, explained
> >>this case in the code and decided to solely rely on the command line
> >>parameter for LRR capability. Rational for this approach is ,
> >
> >This means the systems which you said fixes this would need the command
> >line parameter to work? 
> I feel I do not make things clear enough.
> The command line parameter can be avoided entirely if majority of the 
> BIOSes implement LRR routing correctly. I would rewrite the patch to avoid 

But they don't.

> cmdline parameter and according to Andrew Morton's suggestions.

What was that suggestion again? (sorry can't find it)

Anyways the goal is really to just work everywhere without command line
parameters. Can we somehow detect the SunFire condition and only enable 
it there?

-Andi (who must admit he still doesn't quite understand why the Sun machine
needs this anyways)