Messages in this thread | | | Date | Tue, 24 Aug 2010 23:51:17 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH] x86, apic: Add apic calibration hook. |
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Alok,
On Tue, 24 Aug 2010, Alok Kataria wrote:
> Hi Thomas, > > Thanks for taking a look. > > On Tue, 2010-08-24 at 06:37 -0700, Thomas Gleixner wrote: > > On Wed, 18 Aug 2010, Alok Kataria wrote: > > > > > > +static void __init initialize_lapic_clkevt(long delta) > > > +{ > > > + /* Calculate the scaled math multiplication factor */ > > > + lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS, > > > + lapic_clockevent.shift); > > > + lapic_clockevent.max_delta_ns = > > > + clockevent_delta2ns(0x7FFFFF, &lapic_clockevent); > > > + lapic_clockevent.min_delta_ns = > > > + clockevent_delta2ns(0xF, &lapic_clockevent); > > > +} > > > + > > > static int __init calibrate_APIC_clock(void) > > > { > > > + apic_calibration_res = x86_init.timers.calibrate_apic(); > > > + if (apic_calibration_res) { > > > + struct clock_event_device *levt = &__get_cpu_var(lapic_events); > > > + long delta; > > > + > > > + if (lapic_clockevent.mult) > > > + return 0; > > > > Why is this necessary ? calibrate_APIC_clock() is only called once. > > > > Yes, though timer.calibrate_apci() could behave differently on different > platforms. For eg. the vmware_calibrate_apic doesn't initialize any of > the lapic_clockevent state and we need this to set it up in that case.
Can we please make this consistent ?
Thanks,
tglx
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