commit: 2a2d31c8dc6f1ebcf5eab1d93a0cb0fb4ed57c7c From: Shaohua Li <[email protected]> Date: Mon, 10 Jan 2011 09:38:12 +0800 Subject: [PATCH] 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 <[email protected]> Signed-off-by: Shaohua Li <[email protected]> cc: [email protected] Signed-off-by: Len Brown <[email protected]> --- drivers/idle/intel_idle.c | 47 ++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 46 insertions(+), 1 deletions(-) diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 8256309..fc39358 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; } _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
