Commit-ID: 39fe05e58c5e448601ce46e6b03900d5bf31c4b0
Gitweb: http://git.kernel.org/tip/39fe05e58c5e448601ce46e6b03900d5bf31c4b0
Author: Shaohua Li <shaohua.li@xxxxxxxxx>
AuthorDate: Wed, 12 Aug 2009 11:16:12 +0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 12 Aug 2009 16:45:02 +0200
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: Shaohua Li <shaohua.li@xxxxxxxxx>
Cc: venkatesh.pallipadi@xxxxxxxxx
LKML-Reference: <20090812031612.GA10062@xxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/hpet.c | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
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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