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

[Om Narasimhan <om.turyx@gmail.com>]

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 cmdline parameter and according to Andrew Morton's suggestions.

Thanks,
Om.