x86, hpet: Disable per-cpu hpet timer if ARAT is supported (39fe05e5) · Commits · 戴 / test

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 <shaohua.li@intel.com> Cc: venkatesh.pallipadi@intel.com LKML-Reference: <20090812031612.GA10062@sli10-desk.sh.intel.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/hpet.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -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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