Re: [PATCH] tick: add check for the existence of broadcast clockevent device

From: Thomas Gleixner
Date: Mon Jun 08 2009 - 01:44:03 EST


On Mon, 8 Jun 2009, Feng Tang wrote:
> > 1) How do you calibrate the local APIC timer if you do not have some
> > initial timer device ?
> Yes, we have external timer device with the name "apbt"

So that timer is initialized and registered before the local apic,
right ?

Why is the local APIC timer used at all ? The apbt timer should have a
higher rating as the local APIC timer, so when APIC is registered it
is not selected and the check in the broadcast functions

!(dev->features & CLOCK_EVT_FEAT_C3STOP))

should protect you because that bit is not set on your apbt device.

Thanks,

tglx
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