[patch 3/3] clockevents: Fix resume logic - updated version

Thomas Gleixner
2007-05-06T15:00:31Z

Andrew,

On Sat, 2007-05-05 at 13:51 +0200, Ingo Molnar wrote:
> * Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > > Fixup the existing users.
> >
> > This one makes the Vaio-of-fun hang during suspend to disk. It gets
> > up to "swsusp: critical section/: done (%d pages copied)" then it
> > freezes.
>
> after trying to reproduce it on 2 boxes without success it did trigger
> some sw-suspend weirdness on a third box :) We are debugging it now.

find an updated patch below. It fixes the problem on Ingo's
VAIO-of-fun-emulator and I got confirmation from several other affected
users, that the patch series is still solving their problems.

tglx

------------------------>

Subject: clockevents: Fix resume logic

We need to make sure, that the clockevent devices are resumed, before
the tick is resumed. The current resume logic does not guarantee this.

Add CLOCK_EVT_MODE_RESUME and call the set mode functions of the clock
event devices before resuming the tick / oneshot functionality.

Fixup the existing users.

Fix the PIT handling of CLOCK_EVT_SHUTDOWN by disabling the interrupt
instead of switching to oneshot mode, as this causes slowness on a couple
of systems.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
arch/i386/kernel/apic.c | 3 +
arch/i386/kernel/hpet.c | 71 +++----------------------------------------
arch/i386/kernel/i8253.c | 43 +++++++++++++++++---------
include/linux/clockchips.h | 1
kernel/time/tick-broadcast.c | 4 +-
kernel/time/tick-common.c | 16 ++++++---
6 files changed, 51 insertions(+), 87 deletions(-)

Index: linux-2.6.21/arch/i386/kernel/apic.c
===================================================================
--- linux-2.6.21.orig/arch/i386/kernel/apic.c
+++ linux-2.6.21/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-2.6.21/arch/i386/kernel/hpet.c
===================================================================
--- linux-2.6.21.orig/arch/i386/kernel/hpet.c
+++ linux-2.6.21/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-2.6.21/arch/i386/kernel/i8253.c
===================================================================
--- linux-2.6.21.orig/arch/i386/kernel/i8253.c
+++ linux-2.6.21/arch/i386/kernel/i8253.c
@@ -3,11 +3,11 @@
*
*/
#include <linux/clockchips.h>
-#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
#include <linux/jiffies.h>
-#include <linux/sysdev.h>
#include <linux/module.h>
-#include <linux/init.h>
+#include <linux/spinlock.h>

#include <asm/smp.h>
#include <asm/delay.h>
@@ -25,6 +25,24 @@ EXPORT_SYMBOL(i8253_lock);
*/
struct clock_event_device *global_clock_event;

+/* Status of the PIT interrupt */
+static int pit_irq_disabled;
+
+/*
+ * Control pit interrupt enable / disable
+ */
+static void pit_control_irq(int disable)
+{
+ if (pit_irq_disabled == disable)
+ return;
+
+ pit_irq_disabled = disable;
+ if (disable)
+ disable_irq(0);
+ else
+ enable_irq(0);
+}
+
/*
* Initialize the PIT timer.
*
@@ -41,26 +59,23 @@ static void init_pit_timer(enum clock_ev
case CLOCK_EVT_MODE_PERIODIC:
/* binary, mode 2, LSB/MSB, ch 0 */
outb_p(0x34, PIT_MODE);
- udelay(10);
outb_p(LATCH & 0xff , PIT_CH0); /* LSB */
- udelay(10);
outb(LATCH >> 8 , PIT_CH0); /* MSB */
+ pit_control_irq(0);
break;

- /*
- * Avoid unnecessary state transitions, as it confuses
- * Geode / Cyrix based boxen.
- */
case CLOCK_EVT_MODE_SHUTDOWN:
- if (evt->mode == CLOCK_EVT_MODE_UNUSED)
- break;
case CLOCK_EVT_MODE_UNUSED:
- if (evt->mode == CLOCK_EVT_MODE_SHUTDOWN)
- break;
+ pit_control_irq(1);
+ break;
case CLOCK_EVT_MODE_ONESHOT:
/* One shot setup */
outb_p(0x38, PIT_MODE);
- udelay(10);
+ pit_control_irq(0);
+ break;
+
+ case CLOCK_EVT_MODE_RESUME:
+ /* Nothing to do here */
break;
}
spin_unlock_irqrestore(&i8253_lock, flags);
Index: linux-2.6.21/include/linux/clockchips.h
===================================================================
--- linux-2.6.21.orig/include/linux/clockchips.h
+++ linux-2.6.21/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-2.6.21/kernel/time/tick-broadcast.c
===================================================================
--- linux-2.6.21.orig/kernel/time/tick-broadcast.c
+++ linux-2.6.21/kernel/time/tick-broadcast.c
@@ -292,7 +292,7 @@ void tick_suspend_broadcast(void)
spin_lock_irqsave(&tick_broadcast_lock, flags);

bc = tick_broadcast_device.evtdev;
- if (bc && tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+ if (bc)
clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);

spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -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-2.6.21/kernel/time/tick-common.c
===================================================================
--- linux-2.6.21.orig/kernel/time/tick-common.c
+++ linux-2.6.21/kernel/time/tick-common.c
@@ -318,12 +318,17 @@ static void tick_resume(void)
{
struct tick_device *td = &__get_cpu_var(tick_cpu_device);
unsigned long flags;
+ int broadcast = tick_resume_broadcast();

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);
}

@@ -360,8 +365,7 @@ static int tick_notify(struct notifier_b
break;

case CLOCK_EVT_NOTIFY_RESUME:
- if (!tick_resume_broadcast())
- tick_resume();
+ tick_resume();
break;