Messages in this thread | | | Subject | Re: [PATCH] disable per-cpu hpet timer if ARAT is supported | From | "Pallipadi, Venkatesh" <> | Date | Fri, 14 Aug 2009 14:41:03 -0700 |
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Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
On Tue, 2009-08-11 at 20:16 -0700, Li, Shaohua wrote: > If CPU support always running local APIC timer, per-cpu hpet timer could be > disabled, which is useless and wasteful in such case. Let's leave the timers > to others. > Impact: should have no impact except reserving less timers. > > Signed-off-by: Shaohua Li <shaohua.li@intel.com> > diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c > index dedc2bd..5969e10 100644 > --- a/arch/x86/kernel/hpet.c > +++ b/arch/x86/kernel/hpet.c > @@ -584,6 +584,8 @@ static void hpet_msi_capability_lookup(unsigned int start_timer) > unsigned int num_timers_used = 0; > int i; > > + if (boot_cpu_has(X86_FEATURE_ARAT)) > + return; > id = hpet_readl(HPET_ID); > > num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT); > @@ -872,10 +874,8 @@ int __init hpet_enable(void) > > if (id & HPET_ID_LEGSUP) { > hpet_legacy_clockevent_register(); > - hpet_msi_capability_lookup(2); > return 1; > } > - hpet_msi_capability_lookup(0); > return 0; > > out_nohpet: > @@ -908,9 +908,17 @@ static __init int hpet_late_init(void) > if (!hpet_virt_address) > return -ENODEV; > > + if (hpet_readl(HPET_ID) & HPET_ID_LEGSUP) > + hpet_msi_capability_lookup(2); > + else > + hpet_msi_capability_lookup(0); > + > hpet_reserve_platform_timers(hpet_readl(HPET_ID)); > hpet_print_config(); > > + if (boot_cpu_has(X86_FEATURE_ARAT)) > + return 0; > + > for_each_online_cpu(cpu) { > hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu); > }
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