Use the RTC cmos area to track where suspend/resume hangs
---
 arch/x86/kernel/acpi/realmode/wakemain.c |   22 ++++++++
 drivers/acpi/proc.c                      |   81 +++++++++++++++++++++++++++++++
 drivers/acpi/sleep.c                     |   27 +++++++++-
 3 files changed, 129 insertions(+), 1 deletion(-)

Index: linux-2.6/arch/x86/kernel/acpi/realmode/wakemain.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/acpi/realmode/wakemain.c	2009-04-03 09:16:16.000000000 +0800
+++ linux-2.6/arch/x86/kernel/acpi/realmode/wakemain.c	2009-04-03 09:17:24.000000000 +0800
@@ -1,5 +1,26 @@
 #include "wakeup.h"
 #include "boot.h"
+static void rtc_cmos_write(char value, unsigned char port)
+{
+	outb(port, 0x70);
+	io_delay();
+	outb(value, 0x71);
+	io_delay();
+}
+static void acpi_pm_write_timer(u32 timer)
+{
+#define M_TIME 0x61
+	u32 value;
+	value = timer & 0xff;
+	rtc_cmos_write(value, M_TIME);
+	value = (timer >> 8) & 0xff;
+	rtc_cmos_write(value, M_TIME + 1);
+	value = (timer >> 16) & 0xff;
+	rtc_cmos_write(value, M_TIME + 2);
+	value = (timer >> 24) & 0xff;
+	rtc_cmos_write(value, M_TIME + 3);
+	return;
+}
 
 static void udelay(int loops)
 {
@@ -63,6 +84,7 @@
 
 void main(void)
 {
+	acpi_pm_write_timer(0x8A8A8A8A);
 	/* Kill machine if structures are wrong */
 	if (wakeup_header.real_magic != 0x12345678)
 		while (1);
Index: linux-2.6/drivers/acpi/proc.c
===================================================================
--- linux-2.6.orig/drivers/acpi/proc.c	2009-04-03 09:16:16.000000000 +0800
+++ linux-2.6/drivers/acpi/proc.c	2009-04-03 09:17:24.000000000 +0800
@@ -495,7 +495,86 @@
 	return ACPI_INTERRUPT_HANDLED;
 }
 #endif				/* HAVE_ACPI_LEGACY_ALARM */
+#define CMOS_COUNT 0x60
+#define CMOS_TIME 0x61
+static ssize_t
+acpi_cmos_read(struct file *file,
+			char __user *buffer, size_t count, loff_t *ppos)
+{
+	int result = 0;
+	unsigned long p = *ppos;
+	int mcount;
+	char alarm_string[30] = { '\0' };
+	int mjiffies = 0;
+
+	if (count < sizeof(alarm_string))
+		return 0;
+	if (p >= sizeof(alarm_string))
+		return 0;
+
+	spin_lock_irq(&rtc_lock);
+
+	mcount = CMOS_READ(CMOS_COUNT);
+	result = CMOS_READ(CMOS_TIME);
+	mjiffies = result;
+	result = CMOS_READ(CMOS_TIME + 1);
+	mjiffies += (result << 8);
+	result = CMOS_READ(CMOS_TIME + 2);
+	mjiffies += (result << 16);
+	result = CMOS_READ(CMOS_TIME + 3);
+	mjiffies += (result << 24);
+	spin_unlock_irq(&rtc_lock);
+	sprintf(alarm_string, "mcount=%d, time=%x\n",
+			mcount, mjiffies);
+	printk(KERN_DEBUG "alarm_string is %s\n",
+				alarm_string);
+	result = min(sizeof(alarm_string), count);
+	if (copy_to_user(buffer, alarm_string, result)) {
+		printk(KERN_DEBUG "Copy fail\n");
+		return -EINVAL;
+	}
+	*ppos += result;
+	return result;
+}
+static ssize_t
+acpi_cmos_write(struct file *file,
+			const char __user *buffer, size_t count, loff_t *ppos)
+{
+	int result = 0;
+	int mcount;
+	char alarm_string[30] = { '\0' };
+
+	if (count > sizeof(alarm_string))
+		return 0;
 
+	if (copy_from_user(alarm_string, buffer, count))
+		return 0;
+
+	sscanf(alarm_string, "%d\n", &mcount);
+
+	spin_lock_irq(&rtc_lock);
+
+	CMOS_WRITE(mcount&0xff, CMOS_COUNT);
+	CMOS_WRITE(0xAA, CMOS_TIME);
+	CMOS_WRITE(0xAA, CMOS_TIME + 1);
+	CMOS_WRITE(0xAA, CMOS_TIME + 2);
+	CMOS_WRITE(0xAA, CMOS_TIME + 3);
+
+	spin_unlock_irq(&rtc_lock);
+
+
+	*ppos += count;
+	printk(KERN_DEBUG "cmos write count is %d\n",
+				mcount);
+
+	result = 0;
+	return count;
+}
+static const struct file_operations acpi_cmos_fops = {
+	.owner = THIS_MODULE,
+	.read = acpi_cmos_read,
+	.write = acpi_cmos_write,
+};
 static int __init acpi_sleep_proc_init(void)
 {
 	if (acpi_disabled)
@@ -525,6 +604,8 @@
 	proc_create("wakeup", S_IFREG | S_IRUGO | S_IWUSR,
 		    acpi_root_dir, &acpi_system_wakeup_device_fops);
 
+	proc_create("cmos", S_IRUGO | S_IWUSR, NULL,
+				&acpi_cmos_fops);
 	return 0;
 }
 
Index: linux-2.6/drivers/acpi/sleep.c
===================================================================
--- linux-2.6.orig/drivers/acpi/sleep.c	2009-04-03 09:16:16.000000000 +0800
+++ linux-2.6/drivers/acpi/sleep.c	2009-04-03 09:17:24.000000000 +0800
@@ -22,8 +22,27 @@
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include "sleep.h"
+#include <linux/mc146818rtc.h>
 
 u8 sleep_states[ACPI_S_STATE_COUNT];
+static void acpi_pm_write_timer(u32 timer)
+{
+#define M_TIME 0x61
+	u32 value;
+	unsigned long flags;
+	spin_lock_irqsave(&rtc_lock, flags);
+	value = timer & 0xff;
+	CMOS_WRITE(value, M_TIME);
+	value = (timer >> 8) & 0xff;
+	CMOS_WRITE(value, M_TIME + 1);
+	value = (timer >> 16) & 0xff;
+	CMOS_WRITE(value, M_TIME + 2);
+	value = (timer >> 24) & 0xff;
+	CMOS_WRITE(value, M_TIME + 3);
+
+	spin_unlock_irqrestore(&rtc_lock, flags);
+	return;
+}
 
 static void acpi_sleep_tts_switch(u32 acpi_state)
 {
@@ -235,6 +254,10 @@
 
 	local_irq_save(flags);
 	acpi_enable_wakeup_device(acpi_state);
+	{
+		unsigned long mjiffies = jiffies + 5;
+		acpi_pm_write_timer(mjiffies);
+	}
 	switch (acpi_state) {
 	case ACPI_STATE_S1:
 		barrier();
@@ -245,7 +268,9 @@
 		do_suspend_lowlevel();
 		break;
 	}
-
+	{
+		acpi_pm_write_timer(0xB8B8B8B8);
+	}
 	/* If ACPI is not enabled by the BIOS, we need to enable it here. */
 	if (set_sci_en_on_resume)
 		acpi_set_register(ACPI_BITREG_SCI_ENABLE, 1);