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Subject[09/68] x86, hpet: Disable per-cpu hpet timer if ARAT is supported
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------
From: Shaohua Li <shaohua.li@intel.com>

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 <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>
Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/kernel/hpet.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -606,6 +606,8 @@ static void hpet_msi_capability_lookup(u
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);
}



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