From: Shaohua Li Date: Wed, 12 Aug 2009 03:16:12 +0000 (+0800) Subject: x86, hpet: Disable per-cpu hpet timer if ARAT is supported X-Git-Tag: firefly_0821_release~10186^2~446 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bf8c4fb74755a0b72e013c2bdcdb6a97b544081e;p=firefly-linux-kernel-4.4.55.git x86, hpet: Disable per-cpu hpet timer if ARAT is supported commit 39fe05e58c5e448601ce46e6b03900d5bf31c4b0 upstream. 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. The effect is that we reserve less timers. Signed-off-by: Shaohua Li Cc: venkatesh.pallipadi@intel.com LKML-Reference: <20090812031612.GA10062@sli10-desk.sh.intel.com> Signed-off-by: Ingo Molnar Cc: Thomas Renninger Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index c771e1a37b9d..69cab241341d 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -606,6 +606,8 @@ static void hpet_msi_capability_lookup(unsigned int start_timer) if (hpet_msi_disable) return; + if (boot_cpu_has(X86_FEATURE_ARAT)) + return; id = hpet_readl(HPET_ID); num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT); @@ -894,10 +896,8 @@ 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: @@ -930,12 +930,20 @@ 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 (hpet_msi_disable) return 0; + if (boot_cpu_has(X86_FEATURE_ARAT)) + return 0; + for_each_online_cpu(cpu) { hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu); }