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authorShaohua Li <shaohua.li@intel.com>2011-01-10 04:38:12 +0300
committerLen Brown <len.brown@intel.com>2011-01-12 20:47:34 +0300
commit2a2d31c8dc6f1ebcf5eab1d93a0cb0fb4ed57c7c (patch)
tree24a83ac74e876bac402a99262ac5ac89144810b3 /drivers/idle
parent5392083748a340f68052c0b83a7ce28b10324972 (diff)
downloadlinux-2a2d31c8dc6f1ebcf5eab1d93a0cb0fb4ed57c7c.tar.xz
intel_idle: open broadcast clock event
Intel_idle driver uses CLOCK_EVT_NOTIFY_BROADCAST_ENTER CLOCK_EVT_NOTIFY_BROADCAST_EXIT for broadcast clock events. The _ENTER/_EXIT doesn't really open broadcast clock events, please see processor_idle.c for an example. In some situation, this will cause boot hang, because some CPUs enters idle but local APIC timer stalls. Reported-and-tested-by: Yan Zheng <zheng.z.yan@intel.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> cc: stable@kernel.org Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/idle')
-rw-r--r--drivers/idle/intel_idle.c47
1 files changed, 46 insertions, 1 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 8256309deaad..fc393586cc70 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -59,6 +59,8 @@
#include <linux/hrtimer.h> /* ktime_get_real() */
#include <trace/events/power.h>
#include <linux/sched.h>
+#include <linux/notifier.h>
+#include <linux/cpu.h>
#include <asm/mwait.h>
#define INTEL_IDLE_VERSION "0.4"
@@ -73,6 +75,7 @@ static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;
static unsigned int mwait_substates;
+#define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF
/* Reliable LAPIC Timer States, bit 1 for C1 etc. */
static unsigned int lapic_timer_reliable_states = (1 << 1); /* Default to only C1 */
@@ -252,6 +255,39 @@ static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state)
return usec_delta;
}
+static void __setup_broadcast_timer(void *arg)
+{
+ unsigned long reason = (unsigned long)arg;
+ int cpu = smp_processor_id();
+
+ reason = reason ?
+ CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
+
+ clockevents_notify(reason, &cpu);
+}
+
+static int __cpuinit setup_broadcast_cpuhp_notify(struct notifier_block *n,
+ unsigned long action, void *hcpu)
+{
+ int hotcpu = (unsigned long)hcpu;
+
+ switch (action & 0xf) {
+ case CPU_ONLINE:
+ smp_call_function_single(hotcpu, __setup_broadcast_timer,
+ (void *)true, 1);
+ break;
+ case CPU_DOWN_PREPARE:
+ smp_call_function_single(hotcpu, __setup_broadcast_timer,
+ (void *)false, 1);
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata setup_broadcast_notifier = {
+ .notifier_call = setup_broadcast_cpuhp_notify,
+};
+
/*
* intel_idle_probe()
*/
@@ -314,7 +350,11 @@ static int intel_idle_probe(void)
}
if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
- lapic_timer_reliable_states = 0xFFFFFFFF;
+ lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
+ else {
+ smp_call_function(__setup_broadcast_timer, (void *)true, 1);
+ register_cpu_notifier(&setup_broadcast_notifier);
+ }
pr_debug(PREFIX "v" INTEL_IDLE_VERSION
" model 0x%X\n", boot_cpu_data.x86_model);
@@ -441,6 +481,11 @@ static void __exit intel_idle_exit(void)
intel_idle_cpuidle_devices_uninit();
cpuidle_unregister_driver(&intel_idle_driver);
+ if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {
+ smp_call_function(__setup_broadcast_timer, (void *)false, 1);
+ unregister_cpu_notifier(&setup_broadcast_notifier);
+ }
+
return;
}