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

[Thomas Gleixner <tglx@linutronix.de>]

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;
 
 	default: