Messages in this thread | | | Date | Fri, 27 Oct 2006 09:03:19 +0200 | From | Vojtech Pavlik <> | Subject | Re: HPET : Legacy Routing Replacement Enable - 3rd try. |
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On Fri, Oct 27, 2006 at 09:29:44AM +0300, Mika Penttilä wrote:
> >JFYI: The new per-cpu timekeeping code doesn't need the HPET legacy bit, > >thus not replacing IRQ0 (PIT) and IRQ13 (RTC). It still can do that, but > >will work just as well without it.
> There seems to be lot of confusion here. Current code isn't using hpet > as tick source if legacy is not supported. This patch adds > hpet_lrr_force but it's not clear how it interacts with hpet_use_timer - > in some places it is hpet_use_timer and some (hpet_use_timer && > hpet_lrr_force).
Sorry about my share of confusion introduced: Jiri Bohac (jbohac@suse.cz) is currently working on a new timekeeping code for x86-64 that takes a significantly different approach that allows for precise and fast gettimeofday even on CPUs with unsynchronized TSCs.
This rewrite depends even less on hpet_use_timer than the current code. The current code can cope with hpet_use_timer == 0, but that mode of operation is far from optimal.
> The timer is routed to ioapic pin 2 which is irq0 with source override. > With this patch with hpet_lrr_force=1 timer irq is set to 2 for x86_64 > and 0 for i386, that can't be right?
It doesn't seem right to me, unless someone at Sun really misread the specification when designing the mainboard.
-- Vojtech Pavlik Director SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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