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SubjectRE: [PATCH][2.6][5/5]Support for HPET based timer

> -----Original Message-----
> From: Vojtech Pavlik []
> Indeed. The main problem, however, for me was to decide which
> IRQ to use
> for the HPET. The HPET has a big mask of allowable IRQs, the APIC has
> many pins - so how to decide which one to use and if possible
> not share
> it with a PCI device?

This possibly can be done by selecting the pin that is not already
programmed by
setup_IO_APIC_irqs(), and do a manual setup_IO_APIC_irqs() on that, for

> That'd work probably. I don't believe there will ever be systems with
> HPET and without a working IOAPIC. But, well, insane things do happen.
> As for the user disabling it, we could disable HPET then,
> too. Anyway, I
> agree with your proposal of first going for legacy mode and
> doing native
> mode later.

Thanks for all the comments/suggestions. I will work on using early
ioremap in
place of fixmap and resend the patch.

> (PS. It's a pretty stupid thing in the HPET spec to only be able to
> gobble up BOTH the PIT and RTC interrupts and not separately.)

I totally agree with you. Just one additional bit would have solved the
these problems. Also, I do not understand why RTC interrupts were
at all, when HPET cannot provide complete RTC functionality and it does
know anything about RTC time.


> --
> Vojtech Pavlik
> SuSE Labs, SuSE CR
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