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Commit 39fe05e5 authored by Shaohua Li's avatar Shaohua Li Committed by Ingo Molnar
Browse files

x86, hpet: Disable per-cpu hpet timer if ARAT is supported 



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: default avatarShaohua Li <shaohua.li@intel.com>
Cc: venkatesh.pallipadi@intel.com
LKML-Reference: <20090812031612.GA10062@sli10-desk.sh.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7cb7beb3

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);

	}