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Message-Id: <1177874733.5791.137.camel@localhost.localdomain>
Date: Sun, 29 Apr 2007 21:25:32 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: Indan Zupancic <indan@....nu>
Cc: johnstul@...ibm.com, linux-kernel@...r.kernel.org
Subject: Re: [2.6.21] BUG: clocksource_watchdog isn't reset after resume
On Sun, 2007-04-29 at 18:20 +0200, Indan Zupancic wrote:
> Hello,
>
> After s2ram, basically the following happens, which shouldn't happen:
>
> [ 0.880234] Clocksource tsc unstable (delta = 449782067799 ns)
> [ 0.881221] Time: pit clocksource has been installed.
>
> Looking at the source, it seems that clocksource_watchdog isn't reset
> after resume, while the clock source used is, and hence it thinks that
> the clock is unstable.
Yup, missed that. I was looking into the resume path anyway for other
reasons. Does the patch below fix your problem ?
tglx
Index: linux-2.6/arch/i386/kernel/apic.c
===================================================================
--- linux-2.6.orig/arch/i386/kernel/apic.c
+++ linux-2.6/arch/i386/kernel/apic.c
@@ -242,6 +242,9 @@ static void lapic_timer_setup(enum clock
v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
apic_write_around(APIC_LVTT, v);
break;
+ case CLOCK_EVT_MODE_RESUME:
+ /* Nothing to do here */
+ break;
}
local_irq_restore(flags);
Index: linux-2.6/arch/i386/kernel/hpet.c
===================================================================
--- linux-2.6.orig/arch/i386/kernel/hpet.c
+++ linux-2.6/arch/i386/kernel/hpet.c
@@ -187,6 +187,10 @@ static void hpet_set_mode(enum clock_eve
cfg &= ~HPET_TN_ENABLE;
hpet_writel(cfg, HPET_T0_CFG);
break;
+
+ case CLOCK_EVT_MODE_RESUME:
+ hpet_enable_int();
+ break;
}
}
@@ -217,6 +221,7 @@ static struct clocksource clocksource_hp
.mask = HPET_MASK,
.shift = HPET_SHIFT,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .resume = hpet_start_counter,
};
/*
@@ -291,7 +296,6 @@ int __init hpet_enable(void)
clocksource_register(&clocksource_hpet);
-
if (id & HPET_ID_LEGSUP) {
hpet_enable_int();
hpet_reserve_platform_timers(id);
@@ -524,68 +528,3 @@ irqreturn_t hpet_rtc_interrupt(int irq,
return IRQ_HANDLED;
}
#endif
-
-
-/*
- * Suspend/resume part
- */
-
-#ifdef CONFIG_PM
-
-static int hpet_suspend(struct sys_device *sys_device, pm_message_t state)
-{
- unsigned long cfg = hpet_readl(HPET_CFG);
-
- cfg &= ~(HPET_CFG_ENABLE|HPET_CFG_LEGACY);
- hpet_writel(cfg, HPET_CFG);
-
- return 0;
-}
-
-static int hpet_resume(struct sys_device *sys_device)
-{
- unsigned int id;
-
- hpet_start_counter();
-
- id = hpet_readl(HPET_ID);
-
- if (id & HPET_ID_LEGSUP)
- hpet_enable_int();
-
- return 0;
-}
-
-static struct sysdev_class hpet_class = {
- set_kset_name("hpet"),
- .suspend = hpet_suspend,
- .resume = hpet_resume,
-};
-
-static struct sys_device hpet_device = {
- .id = 0,
- .cls = &hpet_class,
-};
-
-
-static __init int hpet_register_sysfs(void)
-{
- int err;
-
- if (!is_hpet_capable())
- return 0;
-
- err = sysdev_class_register(&hpet_class);
-
- if (!err) {
- err = sysdev_register(&hpet_device);
- if (err)
- sysdev_class_unregister(&hpet_class);
- }
-
- return err;
-}
-
-device_initcall(hpet_register_sysfs);
-
-#endif
Index: linux-2.6/arch/i386/kernel/i8253.c
===================================================================
--- linux-2.6.orig/arch/i386/kernel/i8253.c
+++ linux-2.6/arch/i386/kernel/i8253.c
@@ -62,6 +62,10 @@ static void init_pit_timer(enum clock_ev
outb_p(0x38, PIT_MODE);
udelay(10);
break;
+
+ case CLOCK_EVT_MODE_RESUME:
+ /* Nothing to do here */
+ break;
}
spin_unlock_irqrestore(&i8253_lock, flags);
}
Index: linux-2.6/include/linux/clockchips.h
===================================================================
--- linux-2.6.orig/include/linux/clockchips.h
+++ linux-2.6/include/linux/clockchips.h
@@ -23,6 +23,7 @@ enum clock_event_mode {
CLOCK_EVT_MODE_SHUTDOWN,
CLOCK_EVT_MODE_PERIODIC,
CLOCK_EVT_MODE_ONESHOT,
+ CLOCK_EVT_MODE_RESUME,
};
/* Clock event notification values */
Index: linux-2.6/include/linux/clocksource.h
===================================================================
--- linux-2.6.orig/include/linux/clocksource.h
+++ linux-2.6/include/linux/clocksource.h
@@ -48,6 +48,7 @@ struct clocksource;
* @shift: cycle to nanosecond divisor (power of two)
* @flags: flags describing special properties
* @vread: vsyscall based read
+ * @resume: resume function for the clocksource, if necessary
* @cycle_interval: Used internally by timekeeping core, please ignore.
* @xtime_interval: Used internally by timekeeping core, please ignore.
*/
@@ -61,6 +62,7 @@ struct clocksource {
u32 shift;
unsigned long flags;
cycle_t (*vread)(void);
+ void (*resume)(void);
/* timekeeping specific data, ignore */
cycle_t cycle_last, cycle_interval;
@@ -198,6 +200,7 @@ static inline void clocksource_calculate
extern int clocksource_register(struct clocksource*);
extern struct clocksource* clocksource_get_next(void);
extern void clocksource_change_rating(struct clocksource *cs, int rating);
+extern void clocksource_resume(void);
#ifdef CONFIG_GENERIC_TIME_VSYSCALL
extern void update_vsyscall(struct timespec *ts, struct clocksource *c);
Index: linux-2.6/kernel/time/clocksource.c
===================================================================
--- linux-2.6.orig/kernel/time/clocksource.c
+++ linux-2.6/kernel/time/clocksource.c
@@ -74,6 +74,8 @@ static struct clocksource *watchdog;
static struct timer_list watchdog_timer;
static DEFINE_SPINLOCK(watchdog_lock);
static cycle_t watchdog_last;
+static int watchdog_resumed;
+
/*
* Interval: 0.5sec Treshold: 0.0625s
*/
@@ -98,15 +100,26 @@ static void clocksource_watchdog(unsigne
struct clocksource *cs, *tmp;
cycle_t csnow, wdnow;
int64_t wd_nsec, cs_nsec;
+ int resumed;
spin_lock(&watchdog_lock);
+ resumed = watchdog_resumed;
+ if (unlikely(resumed))
+ watchdog_resumed = 0;
+
wdnow = watchdog->read();
wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
watchdog_last = wdnow;
list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
csnow = cs->read();
+
+ if (unlikely(resumed)) {
+ cs->wd_last = csnow;
+ continue;
+ }
+
/* Initialized ? */
if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
@@ -136,6 +149,13 @@ static void clocksource_watchdog(unsigne
}
spin_unlock(&watchdog_lock);
}
+static void clocksource_resume_watchdog(void)
+{
+ spin_lock(&watchdog_lock);
+ watchdog_resumed = 1;
+ spin_unlock(&watchdog_lock);
+}
+
static void clocksource_check_watchdog(struct clocksource *cs)
{
struct clocksource *cse;
@@ -182,9 +202,34 @@ static void clocksource_check_watchdog(s
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
}
+
+static inline void clocksource_resume_watchdog(void) { }
#endif
/**
+ * clocksource_resume - resume the clocksource(s)
+ */
+void clocksource_resume(void)
+{
+ struct list_head *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocksource_lock, flags);
+
+ list_for_each(tmp, &clocksource_list) {
+ struct clocksource *cs;
+
+ cs = list_entry(tmp, struct clocksource, list);
+ if (cs->resume)
+ cs->resume();
+ }
+
+ clocksource_resume_watchdog();
+
+ spin_unlock_irqrestore(&clocksource_lock, flags);
+}
+
+/**
* clocksource_get_next - Returns the selected clocksource
*
*/
Index: linux-2.6/kernel/time/tick-broadcast.c
===================================================================
--- linux-2.6.orig/kernel/time/tick-broadcast.c
+++ linux-2.6/kernel/time/tick-broadcast.c
@@ -309,6 +309,8 @@ int tick_resume_broadcast(void)
bc = tick_broadcast_device.evtdev;
if (bc) {
+ clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
+
switch (tick_broadcast_device.mode) {
case TICKDEV_MODE_PERIODIC:
if(!cpus_empty(tick_broadcast_mask))
Index: linux-2.6/kernel/time/tick-common.c
===================================================================
--- linux-2.6.orig/kernel/time/tick-common.c
+++ linux-2.6/kernel/time/tick-common.c
@@ -308,16 +308,20 @@ static void tick_suspend(void)
spin_unlock_irqrestore(&tick_device_lock, flags);
}
-static void tick_resume(void)
+static void tick_resume(int broadcast)
{
struct tick_device *td = &__get_cpu_var(tick_cpu_device);
unsigned long flags;
spin_lock_irqsave(&tick_device_lock, flags);
- if (td->mode == TICKDEV_MODE_PERIODIC)
- tick_setup_periodic(td->evtdev, 0);
- else
- tick_resume_oneshot();
+ clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
+
+ if (!broadcast) {
+ if (td->mode == TICKDEV_MODE_PERIODIC)
+ tick_setup_periodic(td->evtdev, 0);
+ else
+ tick_resume_oneshot();
+ }
spin_unlock_irqrestore(&tick_device_lock, flags);
}
@@ -327,6 +331,8 @@ static void tick_resume(void)
static int tick_notify(struct notifier_block *nb, unsigned long reason,
void *dev)
{
+ int res;
+
switch (reason) {
case CLOCK_EVT_NOTIFY_ADD:
@@ -354,8 +360,8 @@ static int tick_notify(struct notifier_b
break;
case CLOCK_EVT_NOTIFY_RESUME:
- if (!tick_resume_broadcast())
- tick_resume();
+ res = tick_resume_broadcast();
+ tick_resume(res);
break;
default:
Index: linux-2.6/kernel/timer.c
===================================================================
--- linux-2.6.orig/kernel/timer.c
+++ linux-2.6/kernel/timer.c
@@ -999,6 +999,8 @@ static int timekeeping_resume(struct sys
unsigned long flags;
unsigned long now = read_persistent_clock();
+ clocksource_resume();
+
write_seqlock_irqsave(&xtime_lock, flags);
if (now && (now > timekeeping_suspend_time)) {
-
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